Biochemistry, Biophysics, and Structural Biology Commons^™

Exploring Chilling Stress And Recovery Dynamics In C4 Perennial Grass Of Miscanthus Sinensis, Karolina Sobańska, Monika Mokrzycka, Martyna Przewoźnik, Tomasz Pniewski, Katarzyna Glowacka

Department of Biochemistry: Faculty Publications

The increasing cultivation of perennial C4 grass known as Miscanthus spp. for biomass production holds promise as a sustainable source of renewable energy. Unlike the sterile triploid hybrid of M. × giganteus, which cannot reproduce through seeds, M. sinensis possesses attributes that could potentially address these limitations by effectively establishing itself through seed propagation. This study aimed to investigate how 18 genotypes of M. sinensis respond to chilling stress and subsequent recovery. Various traits were measured, including growth and biomass yield, the rate of leaf elongation, and a variety of chlorophyll fluorescence parameters, as well as chlorophyll …

Structural Analysis Of Dj-1 Glyoxalase Activity By Mix-And-Inject Serial Synchrotron Crystallography, Coleman Dolamore

Department of Biochemistry: Dissertations, Theses, and Student Research

Observing enzyme structures while they are catalyzing a reaction has been a major goal of both enzymology and structural biology for decades. With the advent of time-resolved serial X-ray crystallography using X-ray free electron lasers (XFELs) and synchrotron sources, enzyme reactions can be monitored in real time in crystallo. Here, we use two different approaches to study related enzymes involved in methylglyoxal detoxification. For human DJ-1, we used pink beam mix-and-inject serial crystallography (MISC) at the Advanced Photon Source (BioCARS 14-ID) to probe the controversial mechanism of DJ-1’s action on methylglyoxal by using serial Laue diffraction. The high flux …

Structural And Biophysical Insights Into Targeting Of Claudin-4 By A Synthetic Antibody Fragment, Satchal K. Erramilli, Pawel K. Dominik, Chinemerem P. Ogbu, Anthony A. Kossiakoff, Alex J. J.

Department of Biochemistry: Faculty Publications

Claudins are a 27-member family of ~25 kDa membrane proteins that integrate into tight junctions to form molecular barriers at the paracellular spaces between endothelial and epithelial cells. As the backbone of tight junction structure and function, claudins are attractive targets for modulating tissue permeability to deliver drugs or treat disease. However, structures of claudins are limited due to their small sizes and physicochemical properties—these traits also make therapy development a challenge. Here we report the development of a synthetic antibody fragment (sFab) that binds human claudin-4 and the determination of a high-resolution structure of it bound to claudin-4/enterotoxin complexes …

Perspectives On Computational Modeling Of Biological Systems And The Significance Of The Sysmod Community, Bhanwar Lal Puniya, Meghna Verma, Chiara Damiani, Shaimaa Bakr, Andreas Dräger

Department of Biochemistry: Faculty Publications

Motivation: In recent years, applying computational modeling to systems biology has caused a substantial surge in both discovery and practical applications and a significant shift in our understanding of the complexity inherent in biological systems.

Results: In this perspective article, we briefly overview computational modeling in biology, highlighting recent advancements such as multiscale modeling due to the omics revolution, single-cell technology, and integration of artificial intelligence and machine learning approaches. We also discuss the primary challenges faced: integration, standardization, model complexity, scalability, and interdisciplinary collaboration. Lastly, we highlight the contribution made by the Computational Modeling of Biological Systems …

Descspim: An Affordable And Easy-To-Build Light-Sheet Microscope Optimized For Tissue Clearing Techniques, Kohei Otomo, Takaki Omura, Yuki Nozawa, Steven J. Edwards, Yukihiko Sato, Yuri Saito, Shigehiro Yagishita, Hitoshi Uchida, Yuki Watakabe, Kiyotada Naitou, Rin Yanai, Naruhiko Sahara, Satoshi Takagi, Ryohei Katayama, Yusuke Iwata, Toshiro Shiokawa, Yoku Hayakawa, Kensuke Otsuka, Haruko Watanabe-Takano, Yuka Haneda, Shigetomo Fukuhara, Miku Fujiwara, Takenobu Nii, Chikara Meno, Naoki Takeshita, Kenta Yashiro, Juan Marcelo Rosales Rocabado, Masaru Kaku, Tatsuya Yamada, Yumiko Oishi, Hiroyuki Koike, Yinglan Cheng, Keisuke Sekine, Jun-Ichiro Koga, Kaori Sugiyama, Kenichi Kimura, Fuyuki Karube, Hyeree Kim, Ichiro Manabe, Tomomi Nemoto, Kazuki Tainaka, Akinobu Hamada, Hjalmar Brismar, Etsuo A. Susaki

Department of Biochemistry: Faculty Publications

Despite widespread adoption of tissue clearing techniques in recent years, poor access to suitable light-sheet fluorescence microscopes remains a major obstacle for biomedical end-users. Here, we present descSPIM (desktopequipped SPIM for cleared specimens), a low-cost ($20,000–50,000), lowexpertise (one-day installation by a non-expert), yet practical do-it-yourself light-sheet microscope as a solution for this bottleneck. Even the most fundamental configuration of descSPIM enables multi-color imaging of whole mouse brains and a cancer cell line-derived xenograft tumor mass for the visualization of neurocircuitry, assessment of drug distribution, and pathological examination by false-colored hematoxylin and eosin staining in a threedimensional manner. Academically open-sourced (https://github.com/dbsbjuntendo/ …

Multifaceted Roles Of Meg3 In Cellular Senescence And Atherosclerosis, Xiao Cheng, Mohamed Sham Shihabudeen Haider Ali, Vijaya Bhaskar Baki, Matthew Moran, Huabo Su, Xinghui Sun

Department of Biochemistry: Faculty Publications

Background and aims: Long noncoding RNAs are involved in the pathogenesis of atherosclerosis. As long non-coding RNAs maternally expressed gene 3 (Meg3) prevents cellular senescence of hepatic vascular endothelium and obesity-induced insulin resistance, we decided to examine its role in cellular senescence and atherosclerosis.

Methods and Results: By analyzing our data and human and mouse data from the Gene Expression Omnibus database, we found that Meg3 expression was reduced in humans and mice with cardiovascular disease, indicating its potential role in atherosclerosis. In Ldlr^−/− mice fed a Western diet for 12 weeks, Meg3 silencing by chemically modified …

Model-Based Comparison Of Biological Organism And Electro-Mechanical System Resiliency Strategies, Nicholas Ratycz

Mechanical Engineering Undergraduate Honors Theses

Bio-inspired design has been used by many engineers to solve difficult problems or to make manufacturing processes more efficient. Biomimetics is the study of implementing the structure or function of biological substances, materials, mechanisms, and processes onto artificial ones that mimic the original. The goal of the BIASD tool is to provide bio-inspiration for engineers by studying the fault-adaptive strategies that biological systems use, rather than just their structure or function. In this thesis, the fault adaptive strategies of both a biological example and that of a real cubesat are compared using three types of model-based system diagrams to show …

Using Artificial (Ai) To Predict A Structure Of Protein Complex, Yiqing Zang

SACAD: Scholarly Activities

Proteins play pivotal roles in essential life processes and elucidating their three-dimensional (3D) structures is crucial for understanding their functions. AlphaFold2, an advanced artificial intelligence-based method developed by Google DeepMind, has emerged as a promising tool for predicting protein structures. In this study, we evaluated the predictive capabilities of AlphaFold2. Our findings highlight AlphaFold2's efficacy in providing valuable insights into protein structure prediction, albeit with certain limitations. While AlphaFold2 represents a significant advancement in the field, its utility is best realized when integrated with complementary experimental approaches. Consequently, combining the strengths of AlphaFold2 with experimental validation remains essential for achieving …

Expression And Purification Of Domain 1 Of The Cards Toxin, Dylan Andrews, Allison Woods, Ahmad Galaleldeen

Posters - 2024

Mycoplasma pneumoniae (Mp) is an atypical bacterium that is linked to various respiratory diseases such as walking pneumonia and asthma. Upon infection, Mp produces a 591-aa virulence factor known as Community Acquired Respiratory Distress Syndrome Toxin (CARDS TX). The crystal structure of this 591-aa cytotoxin reveals a triangular molecule comprised of an N-terminal ADP-ribosylating domain and a Cterminal tandem β-trefoil domain that is responsible for vacuolation of the host’s cells. Based on structural and sequence homology to other ADP ribosylating toxins, the NAD+ binding site has been predicted, yet none of the published structures of the CARDS toxin contain NAD+. …

Cifa And Cifb Expression In Response To Piwi And Aub Knockdown In Jw18 D. Melanogaster Cells, Julieta Alarcon

Posters - 2024

Wolbachia is an intracellular bacterium that is known for inducing cytoplasmic incompatibility (CI) in its Drosophila melanogaster hosts. CI is characterized by embryonic death when males that express cifA and cifB genes mate with unaffected females (Shropshire, Rosenberg, and Bordenstein 2020). PIWI proteins play important roles such as germline determination, spermiogenesis, and transposon silencing (Thomson and Lin 2009). Previous studies have shown that Piwi expression decreases in a developmental window called the “Piwiless pocket” or Pilp. When Aub is depleted in the Pilp, then Piwi expression increases (Théron et al. 2018). We will determine if Piwi and Aub FANA ASO …

Identification Of A Novel Target For Declustering Supernumerary Centrosomes In Triple Negative Breast Cancer, Priyanga J

Theses and Dissertations

Triple-negative breast cancer (TNBC) confers considerable interventional challenge owing to its massive heterogeneity, aggression and metastatic prowess. These facets are attributed to chromosomal instability (CIN), a feature consequent to TNBC cell’s ability to harbor more than two centrosomes (supernumerary centrosomes; SNCs).

In principle, if a normal cell possesses SNCs, uneven pull forces are generated consequent to multipolar spindle, which activates cellular surveillance. This ensures error-free mitosis by either repairing the error or, in an irreparable condition, driving cells to death. This averts the possibility of aneuploidy (fundamental to tumorigenesis).

Unfortunately, TNBC cells, despite harboring SNCs, have devised a survival strategy …

Vitamin E Biofortification: Enhancement Of Seed Tocopherol Concentrations By Altered Chlorophyll Metabolism, Ping Qin, Peng Chen, Yuanwei Zhou, Wei Zhang, Yunyun Zhang, Jingjing Xu, Lu Gan, Yingnan Liu, Jill Romer, Peter Dörmann, Edgar B. Cahoon, Chunyu Zhang

Department of Biochemistry: Faculty Publications

Homogentisate Phytyltransferase (HPT) catalyzes condensation of homogentisate (HGA) and phytyl diphosphate (PDP) to produce tocopherols, but can also synthesize tocotrienols using geranylgeranyl diphosphate (GGDP) in plants engineered for deregulated HGA synthesis. In contrast to prior tocotrienol biofortification efforts, engineering enhanced tocopherol concentrations in green oilseeds has proven more challenging due to the integral role of chlorophyll metabolism in supplying the PDP substrate. This study show that RNAi suppression of CHLSYN coupled with HPT overexpression increases tocopherol concentrations by >two-fold in Arabidopsis seeds. We obtained additional increases in seed tocopherol concentrations by engineering increased HGA production via overexpression of …

Chromosome‑Level Assembly And Analysis Of Camelina Neglecta: A Novel Diploid Model For Camelina Biotechnology Research, Shuo Wang, Rostislav Y. Blume, Zhi‑Wei Zhou, Shaoping Lu, Tara J. Nazarenus, Yaroslav B. Blume, Weibo Xie, Edgar B. Cahoon, Ling‑Ling Chen, Liang Guo

Department of Biochemistry: Faculty Publications

Camelina neglecta is a new diploid Brassicaceae species, which has great research value because of its close relationship with the hexaploid oilseed crop Camelina sativa. Here, we report a chromosome-level assembly of C. neglecta with a total length of 210 Mb. By adopting PacBio sequencing and Hi-C technology, the C. neglecta genome was assembled into 6 chromosomes with scaffold N50 of 29.62 Mb. C. neglecta has undergone the whole-genome triplication (γ) shared among eudicots and two whole-genome duplications (α and β) shared by crucifers, but it has not undergone a specific whole-genome duplication event. By synteny analysis …

Metabolic Collaboration Between Cells In The Tumor Microenvironment Has A Negligible Effect On Tumor Growth, Johan Gustafsson, Fariba Roshanzamir, Anders Hagnestål, Sagar M. Patel, Oseeyi I. Daudu, Donald F. Becker, Jonathan L. Robinson, Jens Nielsen

Department of Biochemistry: Faculty Publications

The tumor microenvironment is composed of a complex mixture of different cell types interacting under conditions of nutrient deprivation, but the metabolism therein is not fully understood due to difficulties in measuring metabolic fluxes and exchange of metabolites between different cell types in vivo. Genome-scale metabolic modeling enables estimation of such exchange fluxes as well as an opportunity to gain insight into the metabolic behavior of individual cell types. Here, we estimated the availability of nutrients and oxygen within the tumor microenvironment using concentration measurements from blood together with a metabolite diffusion model. In addition, we developed an approach …

Emerging Roles Of Cullin-Ring Ubiquitin Ligases In Cardiac Development, Josue Zambrano-Carrasco, Jianqiu Zou, Wenjuan Wang, Xinghui Sun, Jie Li, Huabo Su

Department of Biochemistry: Faculty Publications

Heart development is a spatiotemporally regulated process that extends from the embryonic phase to postnatal stages. Disruption of this highly orchestrated process can lead to congenital heart disease or predispose the heart to cardiomyopathy or heart failure. Consequently, gaining an in-depth understanding of the molecular mechanisms governing cardiac development holds considerable promise for the development of innovative therapies for various cardiac ailments. While significant progress in uncovering novel transcriptional and epigenetic regulators of heart development has been made, the exploration of post-translational mechanisms that influence this process has lagged. Culling-RING E3 ubiquitin ligases (CRLs), the largest family of ubiquitin ligases, …

Augusta: From Rna-Seq To Gene Regulatory Networks And Boolean Models, Jana Musilova, Zdenek Vafek, Bhanwar Lal Puniya, Ralf Zimmer, Tomáš Helikar, Karel Sedlar

Department of Biochemistry: Faculty Publications

Computational models of gene regulations help to understand regulatory mechanisms and are extensively used in a wide range of areas, e.g., biotechnology or medicine, with significant benefits. Unfortunately, there are only a few computational gene regulatory models of whole genomes allowing static and dynamic analysis due to the lack of sophisticated tools for their reconstruction. Here, we describe Augusta, an open-source Python package for Gene Regulatory Network (GRN) and Boolean Network (BN) inference from the high-throughput gene expression data. Augusta can reconstruct genome-wide models suitable for static and dynamic analyses. Augusta uses a unique approach where the first estimation of …

The Multifunctional Catalytic Hemoglobin Fromamphitrite Ornata: Protocols On Isolation, Taxonomic Identification, Protein Extraction, Purification, And Characterization, Anna L. Husted, Lauren A. Presnar, R. Kevin Blackburn, Joseph L. Staton, Stephen A. Borgiani, Edward L. D'Antonio

Natural Sciences Faculty Publications

The multifunctional catalytic hemoglobin from the terebellid polychaete Amphitrite ornata, also named dehaloperoxidase (AoDHP), utilizes the typical oxygen transport function in addition to four observed activities involved in substrate oxidation. The multifunctional ability of AoDHP is presently a rare observation, and there exists a limitation for how novel dehaloperoxidases can be identified from macrobenthic infauna. In order to discover more infaunal DHP-bearing candidates, we have devised a facilitated method for an accurate taxonomic identification that places visual and molecular taxonomic approaches in parallel. Traditional visual taxonomic species identification by the non-specialist, at least for A. ornata or even for other …

Single-Molecule Pulldown (Simpull) For Detection Of Gpcr Complexes In Mammalian Cells, Julie M. Kraft

Theses and Dissertations

G protein-coupled receptors (GPCRs) constitute the most numerous and diverse superfamily of cell membrane receptors. While GPCRs can perform signal transduction as monomers, evidence suggests they also function as homo- and hetero- dimers and oligomers. These diverse quaternary structures can affect GPCRs’ downstream cellular signaling, pharmacological properties, and regulation of internalization.

The single-molecule pulldown (SiMPull) assay combines a co-immunoprecipitation assay with single-molecule total internal reflection fluorescence (TIRF) microscopy and can be used to probe the stoichiometry of GPCR oligomers in mammalian cells.

This project replicates the SiMPull assay by confirming the quaternary structure of mGluR2 homodimers. Plasmid constructs SNAP-mGluR2-HA and …

Analyzing Functional Interactions Of Designed Peptides By Nmr Spectroscopy, Wonsuk Choi

Pharmaceutical Sciences (MS) Theses

The development of small peptide-based therapeutics can be accelerated by the knowledge of relationships between the peptide structure and its functional interactions. Here, we report the analysis of two groups of synthetic peptides designed for two applications – broad bactericidal action and inhibition of protein-protein interactions in human cells. Novel amphiphilic peptides designed for antibacterial application incorporated arginine as cationic amino acids and non-natural amino acids that have aromatic side chains with similar hydrophobic properties as tryptophan. The interaction of lead cyclic peptides and their linear analogs with a phospholipid bilayer mimicking a bacterial membrane was studied using nuclear magnetic …

Exploring The Impact Of High-Temperature Stress On Physiological, Anatomical, Molecular, Productive, And Quality Parameters In Diverse Olive Cultivars, Bassam F. Alowaiesh, Taghreed S. Alnusaire

The Philippine Agricultural Scientist

Olive (Olea europaea L.) is one of the most important horticultural crops in Saudi Arabia. High temperatures are typical in most regions during the summer season. This study explored the effect of high temperatures on diverse olive cultivars (Manzanillo, Chemlali, and Picual) grown in three different geographical locations in Saudi Arabia (Sakaka, Basita, and Al-Qurayyat). Sakaka region was classified as a hot region, while the Basita and Al-Qurayyat regions were characterized by relatively mild or low temperatures. Genotypic components were assessed by studying Amplified Fragment Length Polymorphism (AFLP) molecular markers and physiological, anatomical, productive, and oil quality parameters. The …

Evaluating The Response Of Glycine Soja Accessions To Fungal Pathogen Macrophomina Phaseolina During Seedling Growth, Shirley Jacquet, Layla Rashad, Sonia Viera, Francisco Reta, Juan Reta

Biological Science Student Working Papers

Charcoal rot caused by the fungal pathogen Macrophomina phaseolina (Tassi) Goid is one of various devastating soybean (Glycine max (L.) Merr.) diseases, which can severely reduce crop yield. The investigation into the genetic potential for charcoal rot resistance of wild soybean (Glycine soja) accessions will enrich our understanding of the impact of soybean domestication on disease resistance; moreover, the identified charcoal rot-resistant lines can be used to improve soybean resistance to charcoal rot. The objective of this study was to evaluate the resistance of wild soybean accessions to M. phaseolina at the seedling stage and thereby select the disease-resistant lines. …

Changes In Lipid Profiles Of Epileptic Mouse Model, Alicia Johnson, Ryan A. Grove, Deepak Madhavan, Cory Honsinger Thomas Boone, Camila Pereira Braga, Hannah Kyllo, Kaeli Samson, Timothy Simeone, Tomáš Helikar, Corrine K. Hanson, Jiri Adamec

Department of Biochemistry: Faculty Publications

Introduction—Approximately 1% of the world’s population is impacted by epilepsy, a chronic neurological disorder characterized by seizures. One-third of epileptic patients are resistant to AEDs, or have medically refractory epilepsy (MRE). One non-invasive treatment that exists for MRE includes the ketogenic diet, a high-fat, low-carbohydrate diet. Despite the KD’s success in seizure attenuation, it has a few risks and its mechanisms remain poorly understood. The KD has been shown to improve metabolism and mitochondrial function in epileptic phenotypes. Potassium channels have implications in epileptic conditions as they have dual roles as metabolic sensors and control neuronal excitation.

Objectives—The …

Bola3 And Nfu1 Link Mitoribosome Iron–Sulfur Cluster Assembly To Multiple Mitochondrial Dysfunctions Syndrome, Hui Zhong, Alexandre Janer, Oleh Khalimonchuk, Hana Antonicka, Eric A. Shoubridge, Antoni Barrientos

Department of Biochemistry: Faculty Publications

The human mitochondrial ribosome contains three [2Fe–2S] clusters whose assembly pathway, role, and implications for mitochondrial and metabolic diseases are unknown. Here, structure-function correlation studies show that the clusters play a structural role during mitoribosome assembly. To uncover the assembly pathway, we have examined the effect of silencing the e xpression of Fe–S cluster biosynthetic and delivery factors on mitoribosome stability. We find that the mitoribosome receives its [²Fe–2S] clusters from the GLRX5-BOLA3 node. Additionally, the assembly of the small subunit depends on the mitoribosome biogenesis factor METTL17, recently reported containing a [⁴Fe–4S] cluster, which we …

Raman Spectral Cytopathology For Cancer Diagnostic Applications, Fiona Lyng, Damian Traynor, Isha Behl, Declan O'Dea, Hugh Byrne

Books/Book Chapters

Histopathology is currently regarded as the “gold standard” patient sampling technique for cancer diagnostics. It involves extraction of a tissue sample, or biopsy, which is then sectioned and stained for evaluation by a pathologist [1]. Cytopathology, on the other hand, is the field of disease diagnosis at the cellular level [2], necessitating only the microscopic evaluation of samples of cells which can be harvested by less invasive methods such as exfoliative brushing, needle probes or from biofluids. Based on the identification of abnormalities in cellular appearance, cytopathology is currently widely used to aid in the screening of cancer, as well …

Factors Influencing Instructors’ Adoption And Continued Use Of Computing Science Technologies: A Case Study In The Context Of Cell Collective, Changsoo Song, Resa M. Helikar, Wendy Smith, Tomáš Helikar

Department of Biochemistry: Faculty Publications

Acquiring computational modeling and simulation skills has become ever more critical for students in life sciences courses at the secondary and tertiary levels. Many modeling and simulation tools have been created to help instructors nurture those skills in their classrooms. Understanding the factors that may motivate instructors to use such tools is crucial to improve students’ learning, especially for having authentic modeling and simulation learning experiences. This study designed and tested a decomposed technology acceptance model in which the perceived usefulness and perceived ease of use constructs are split between the teaching and learning sides of the technology to examine …

Modeling Nonsegmented Negative-Strand Rna Virus (Nnsv) Transcription With Ejective Polymerase Collisions And Biased Diffusion, Felipe-Andres Piedra

Research Symposium

Background: The textbook model of NNSV transcription predicts a gene expression gradient. However, multiple studies show non-gradient gene expression patterns or data inconsistent with a simple gradient. Regarding the latter, several studies show a dramatic decrease in gene expression over the last two genes of the respiratory syncytial virus (RSV) genome (a highly studied NNSV). The textbook model cannot explain these phenomena.

Methods: Computational models of RSV and vesicular stomatitis virus (VSV – another highly studied NNSV) transcription were written in the Python programming language using the Scientific Python Development Environment. The model code is freely available on GitHub: …

Nanodiscs: A Novel Approach To The Study Of The Methionine Abc Transporter System, Michael T. Winslow

Master's Theses

Membrane transporter proteins play the vital role of moving compounds in and out of the cell and are essential for all living organisms. ATP Binding Cassette (ABC) family transporters function both as importers and exporters in prokaryotes. MetNI is an E. coli Type I ABC transporter responsible for the uptake of methionine into the cytosol from the cell periplasmic space through the cell membrane to maintain intracellular methionine pools. ABC transporters, like other membrane proteins, are most often mechanistically and structurally studied in vitro, solubilized by detergents. However, detergent micelles may affect the conformational changes of membrane proteins relative to …

Fbg Αc 389 – 402 Modulates Factor Xiii Crosslinking In The Fibrinogen Αc Region., Francis Dean Orlina Ablan

Electronic Theses and Dissertations

Fibrinogen (Fbg) is a coagulation protein critical for clot formation. Coagulation Factor XIII (FXIII) is a calcium-dependent transglutaminase that crosslinks reactive glutamines (Q) and lysines (K) between fibrin and other anti-fibrinolytic proteins. In the presence of Ca²⁺, FXIII could be activated non-proteolytically (FXIII-A°), or proteolytically by thrombin (FXIII-A*). Significant increases in clot stability and red blood cell retention are linked to FXIII activity in the fibrinogen αC region (Fbg Aα 221 – 610). This region contains several FXIII-reactive glutamines and lysines, as well as a binding site for FXIII-A* (Fbg αC 389 – 402) that includes a key …

Cobalt-Sulfur Coordination Chemistry Drives B12 Loading Onto Methionine Synthase, Romila Mascarenhas, Arkajit Guha, Zhu Li, Markus Ruetz, Sojin An, Javier Seravalli, Ruma Banerjee

Department of Biochemistry: Faculty Publications

Cobalt-sulfur (Co-S) coordination is labile to both oxidation and reduction chemistry and is rarely seen in Nature. Cobalamin (or vitamin B12) is an essential cobalt-containing organometallic cofactor in mammals, and is escorted via an intricate network of chaperones to a single cytoplasmic target, methionine synthase. In this study, we report that the human cobalamin trafficking protein, MMADHC, exploits the chemical lability of Co-S coordination, for cofactor off-loading onto methionine synthase. Cys-261 on MMADHC serves as the -axial ligand to cobalamin. Complex formation between MMADHC and methionine synthase is signaled by loss of the lower axial nitrogen ligand, leading to five-coordinate …

Pyrroline-5-Carboxylate Reductase-2 Promotes Colorectal Carcinogenesis By Modulating Microtubule-Associated Serine/Threonine Kinase-Like/Wnt/Β-Catenin Signaling, Raju Lama Tamang, Balawant Kumar, Sagar M. Patel, Ishwor Thapa, Alshomrani Ahmad, Vikas Kumar, Rizwan Ahmad, Donald F. Becker, Dundy Kiran Bastola, Punita Dhawan, Amar B. Singh

Department of Biochemistry: Faculty Publications

Background: Despite significant progress in clinical management, colorectal cancer (CRC) remains the third most common cause of cancer-related deaths. A positive association between PYCR2 (pyrroline-5-carboxylate reductase-2), a terminal enzyme of proline metabolism, and CRC aggressiveness was recently reported. However, how PYCR2 promotes colon carcinogenesis remains ill understood. Methods: A comprehensive analysis was performed using publicly available cancer databases and CRC patient cohorts. Proteomics and biochemical evaluations were performed along with genetic manipulations and in vivo tumor growth assays to gain a mechanistic understanding. Results: PYCR2 expression was significantly upregulated in CRC and associated with poor patient survival, specifically among PYCR …