Life Sciences Commons^™

(R)-Β-Lysine Modified Elongation Factor P Functions In Translation Elongation, Tammy J. Bullwinkle, S. Betty Zou, Andrei Rajkovic, Steven J. Hersch, Sara Elgamal, Nathaniel Robinson, David Smil, Yuri Bolshan, William Wiley Navarre, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Post-translational modification of bacterial elongation factor P (EF-P) with (R)-β-lysine at a conserved lysine residue activates the protein in vivo and increases puromycin reactivity of the ribosome in vitro. The additional hydroxylation of EF-P at the same lysine residue by the YfcM protein has also recently been described. The roles of modified and unmodified EF-P during different steps in translation, and how this correlates to its physiological role in the cell, have recently been linked to the synthesis of polyproline stretches in proteins. Polysome analysis indicated that EF-P functions in translation elongation, rather than initiation as proposed previously. This was …

Morc2 Signaling Integrates Phosphorylation-Dependent, Atpase-Coupled Chromatin Remodeling During The Dna Damage Response, Da-Qiang Li, Sujit S. Nair, Kazufumi Ohshiro, Anupam Kumar, Vasudha S. Nair, Suresh B. Pakala, Sirigiri Divijendra Natha Reddy, Rajendra P. Gajula, Jeyanthy Eswaran, L. Aravind, Rakesh Kumar

Biochemistry and Molecular Medicine Faculty Publications

Chromatin dynamics play a central role in maintaining genome integrity, but how this is achieved remains largely unknown. Here, we report that microrchidia CW-type zinc finger 2 (MORC2), an uncharacterized protein with a derived PHD finger domain and a conserved GHKL-type ATPase module, is a physiological substrate of p21-activated kinase 1 (PAK1), an important integrator of extracellular signals and nuclear processes. Following DNA damage, MORC2 is phosphorylated on serine 739 in a PAK1-dependent manner, and phosphorylated MORC2 regulates its DNA-dependent ATPase activity to facilitate chromatin remodeling. Moreover, MORC2 associates with chromatin and promotes gamma-H2AX induction in a PAK1 phosphorylation-dependent manner. …

A Comparison Of Boltzmann And Gibbs Definitions Of Microcanonical Entropy For Small Systems, Randall B. Shirts

Faculty Publications

Two different definitions of entropy, S= klnW, in the microcanonical ensemble have been competing for over 100 years. The Boltzmann/Planck definition is that W is the number of states accessible to the system at its energy E (also called the surface entropy). The Gibbs/Hertz definition is that W is the number of states of the system up to the energy E (also called the volume entropy). These two definitions agree for large systems but differ by terms of order N^-1 for small systems, where N is the number of particles in the system. For three analytical …

Crystal Structures And Kinetics Of Monofunctional Proline Dehydrogenase Provide Insight Into Substrate Recognition And Conformational Changes Associated With Flavin Reduction And Product Release, Min Luo, Benjamin W. Arentson, Dhiraj Srivastava, Donald F. Becker, John J. Tanner

Department of Biochemistry: Faculty Publications

Proline dehydrogenase catalyzes the FAD-dependent oxidation of proline to Δ1- pyrroline-5- carboxylate, which is the first step of proline catabolism. Here, we report the structures of proline dehydrogenase from Deinococcus radiodurans in the oxidized state complexed with the proline analog L-tetrahydrofuroic acid and in the reduced state with the proline site vacant. The analog binds against the si face of the FAD isoalloxazine and is protected from bulk solvent by the α8 helix and the β1-α1 loop. The FAD ribityl chain adopts two conformations in the E-S complex, which is unprecedented for flavoenzymes. One of the conformations is novel for …

Selection Of Trna Charging Quality Control Mechanisms That Increase Mistranslation Of The Genetic Code, Srujana S. Yadavalli, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Mistranslation can follow two events during protein synthesis: production of non-cognate amino acid:transfer RNA (tRNA) pairs by aminoacyl-tRNA synthetases (aaRSs) and inaccurate selection of aminoacyl-tRNAs by the ribosome. Many aaRSs actively edit non-cognate amino acids, but editing mechanisms are not evolutionarily conserved, and their physiological significance remains unclear. To address the connection between aaRSs and mistranslation, the evolutionary divergence of tyrosine editing by phenylalanyl-tRNA synthetase (PheRS) was used as a model. Certain PheRSs are naturally error prone, most notably a Mycoplasma example that displayed a low level of specificity consistent with elevated mistranslation of the proteome. Mycoplasma PheRS was found …

Transcription-Coupled Dna Supercoiling In Escherichia Coli: Mechanisms And Biological Functions, Xiaoduo Zhi

FIU Electronic Theses and Dissertations

Transcription by RNA polymerase can induce the formation of hypernegatively supercoiled DNA both in vivo and in vitro. This phenomenon has been explained by a “twin-supercoiled-domain” model of transcription where a positively supercoiled domain is generated ahead of the RNA polymerase and a negatively supercoiled domain behind it. In E. coli cells, transcription-induced topological change of chromosomal DNA is expected to actively remodel chromosomal structure and greatly influence DNA transactions such as transcription, DNA replication, and recombination.

In this study, an IPTG-inducible, two-plasmid system was established to study transcription-coupled DNA supercoiling (TCDS) in E. coli topA strains. By performing topology …

Glutaredoxin 2 (Grx2) Knockout Increases Sensitivity To Oxidative Stress In Mouse Lens Epithelial Cells, Hongli Wu, Liren Lin, Frank Giblin, Ye-Sheh Ho, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Glutaredoxin belongs to the oxidoreductase family with cytosolic glutaredoxin 1 (Grx1) and mitochondrial gluraredoxin 2 (Grx2) isoforms. Of the two isozymes, the function of Grx2 is not well understood. This paper studied the effect of Grx2 deletion on cellular function using primary lens epithelial cell cultures isolated from Grx2 gene knockout (KO) and wild type (WT) mice. We found that both cell types showed similar growth patterns and morphology, and comparable mitochondrial glutathione pool and complex I activity. Cells with deleted Grx2 did not show affected Grx1 or thioredoxin (Trx) expression but exhibited high sensitivity to oxidative stress. Under treatment …

Tumour Inflammasome-Derived Il-1b Recruits Neutrophils And Improves Local Recurrence-Free Survival In Ebv-Induced Nasopharyngeal Carcinoma, Lih-Chyang Chen, Li-Jie Wang, Nang-Ming Tsang, David M. Ojcius, Chia-Chen Chen, Chun-Nan Ouyang, Chuen Hsueh, Ying Liang, Kai-Ping Chang, Chiu-Chin Chen, Yu-Sun Chang

All Dugoni School of Dentistry Faculty Articles

Inflammasomes sense infection and cellular damage and are critical for triggering inflammation through IL-1β production. In carcinogenesis, inflammasomes may have contradictory roles through facilitating antitumour immunity and inducing oncogenic factors. Their function in cancer remains poorly characterized. Here we show that the NLRP3, AIM2 and RIG-I inflammasomes are overexpressed in Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC), and expression levels correlate with patient survival. In tumour cells, AIM2 and RIG-I are required for IL-1β induction by EBV genomic DNA and EBV-encoded small RNAs, respectively, while NLRP3 responds to extracellular ATP and reactive oxygen species. Irradiation and chemotherapy can further activate AIM2 …

Reversible Inhibition Of Chlamydia Trachomatis Infection In Epithelial Cells Due To Stimulation Of P2x4 Receptors, Matthew A. Pettengill, Camila Marques-Da-Silva, Maria Luisa Avila, Verissa W. Lam, Ikechukwu Ollawa, Ali Abdul-Sater, Robson Coutinho-Silva, Georg Hacker, David M. Ojcius, Suellen D'Arc Dos Santos Oliveira

All Dugoni School of Dentistry Faculty Articles

Bacterial infections of the mucosal epithelium are a major cause of human disease. The prolonged presence of microbial pathogens stimulates inflammation of the local tissues, which leads to changes in the molecular composition of the extracellular milieu. A well-characterized molecule that is released to the extracellular milieu by stressed or infected cells is extracellular ATP and its ecto-enzymatic degradation products, which function as signaling molecules through ligation of purinergic receptors. There has been little information, however, on the effects of the extracellular metabolites on bacterial growth in inflamed tissues. Millimolar concentrations of ATP have been previously shown to inhibit irreversibly …

Secondary Structure, A Missing Component Of Sequence- Based Minimotif Definitions, David P. Sargeant, Michael R. Gryk, Mark W. Maciejewsk, Vishal Thapar, Vamsi Kundeti, Sanguthevar Rajasekaran, Pedro Romero, Keith Dunker, Shun-Cheng Li, Tomonori Kaneko, Martin Schiller

Life Sciences Faculty Research

Minimotifs are short contiguous segments of proteins that have a known biological function. The hundreds of thousands of minimotifs discovered thus far are an important part of the theoretical understanding of the specificity of protein-protein interactions, posttranslational modifications, and signal transduction that occur in cells. However, a longstanding problem is that the different abstractions of the sequence definitions do not accurately capture the specificity, despite decades of effort by many labs. We present evidence that structure is an essential component of minimotif specificity, yet is not used in minimotif definitions. Our analysis of several known minimotifs as case studies, analysis …

Immunoproteomics: The Key To Discovery Of New Vaccine Antigens Against Bacterial Respiratory Infections, Ruth Dennehy, Siobhan Mcclean

Articles

The increase in antibiotic resistance and the shortage of new antimicrobials to prevent difficult bacterial infections underlines the importance of prophylactic therapies to prevent infection by bacterial pathogens. Vaccination has reduced the incidence of many serious diseases, including respiratory bacterial infections. However, there are many pathogens for which no vaccine is available and some vaccines are not effective among all age groups or among immunocompromised individuals. Immunoproteomics is a powerful technique which has been used to identify potential vaccine candidates to protect against pathogenic bacteria. The combination of proteomics with the detection of immunoreactive antigens using serum highlights immunogenic proteins …

Knockout Of The 15 Kda Selenoprotein Protects Against Chemically-Induced Aberrant Crypt Formation In Mice, Petra A. Tsuji, Bradley A. Carlson, Salvador Naranjo-Suarez, Min-Hyuk Yoo, Xue-Ming Xu, Dmitri E. Fomenko, Vadim Gladyshev, Dolph L. Hatfield, Cindy D. Davis

Department of Biochemistry: Faculty Publications

Evidence suggests that selenium has cancer preventive properties that are largely mediated through selenoproteins. Our previous observations demonstrated that targeted down-regulation of the 15 kDa selenoprotein (Sep15) in murine colon cancer cells resulted in the reversal of the cancer phenotype. The present study investigated the effect of Sep15 knockout in mice using a chemically-induced colon cancer model. Homozygous Sep15 knockout mice, and wild type littermate controls were given four weekly subcutaneous injections of azoxymethane (10 mg/kg). Sep15 knockout mice developed significantly (pGBP-1 in humans has been associated with a highly significant, increased five-year survival rate in colorectal cancer patients. In …

Structure-Function Analysis Of A Protein Encoded By The Bhv-1 Latency Related Gene, Devis Sinani

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Bovine herpes virus 1 (BHV-1) is a significant viral pathogen in cattle that induces a myriad of clinical symptoms. These symptoms include: conjunctivitis, upper respiratory tract infections, genital disorders, and abortions. BHV-1 infection can also lead to transient immune-suppression, which predisposes cattle to secondary bacterial infection leading to life-threatening pneumonia referred to as bovine respiratory disease (BRD). Following acute infection, BHV-1 establishes latency in sensory neurons within trigeminal ganglia. Reactivation of the virus can occur periodically, resulting in virus transmission. The latency-related (LR) RNA is the only abundantly expressed transcript in latently infected sensory neurons and it encodes several proteins, …

Sinusoidal Endothelial Dysfunction In Non-Alcoholic Fatty Liver Disease., Sandhya Lakshmi Gopalakrishnan

Department of Biochemistry: Dissertations, Theses, and Student Research

Non-alcoholic fatty liver disease (NAFLD) is an asymptomatic increasingly common disorder that affects liver metabolism and is often the precursor for liver pathologies such as fibrosis, cirrhosis and hepato-cellular carcinoma. The liver sinusoidal endothelial cells act as a liver sieve by allowing macromolecules and chylomicrons to traverse through their fenestrations (sieve plates) to hepatocytes. Since liver sinusoidal endothelial cells (LSEC) regulate serum derived macromolecular exposure to hepatocytes, we asked what role LSEC could play in the pathogenesis of NAFLD. To investigate the early events of NAFLD we used a rat model (Sprague-Dawley) in which animals were maintained on standard and …

Medicinal Plants: A Public Resource For Metabolomics And Hypothesis Development, Eve Syrkin Wurtele, Joe Chappell, A. Daniel Jones, Mary Dawn Celiz, Nick Ransom, Manhoi Hur, Ludmila Rizshsky, Matthew Crispin, Philip Dixon, Jia Liu, Mark P. Widrlechner, Basil J. Nikolau

Molecular and Cellular Biochemistry Faculty Publications

Specialized compounds from photosynthetic organisms serve as rich resources for drug development. From aspirin to atropine, plant-derived natural products have had a profound impact on human health. Technological advances provide new opportunities to access these natural products in a metabolic context. Here, we describe a database and platform for storing, visualizing and statistically analyzing metabolomics data from fourteen medicinal plant species. The metabolomes and associated transcriptomes (RNAseq) for each plant species, gathered from up to twenty tissue/organ samples that have experienced varied growth conditions and developmental histories, were analyzed in parallel. Three case studies illustrate different ways that the data …

Complex Of Myoglobin With Phenol Bound In A Proximal Cavity, Xiao Huang, Chunxue Wang, Lesa R. Celeste, Leslie L. Lovelace, Shengfang Sun, John H. Dawson, Lukasz Lebioda

Faculty Publications

Sperm whale myoglobin (Mb) has weak dehaloperoxidase activity and catalyzes the peroxidative dehalogenation of 2,4,6-trichlorophenol (TCP) to 2,6-dichloroquinone. Crystals of Mb and of its more active G65T variant were used to study the binding of TCP, 4-iodophenol (4-IP) and phenol. The structures of crystals soaked overnight in a 10 mM solution of phenol revealed that a phenol molecule binds in the proximal cavity, forming a hydrogen bond to the hydroxyl of Tyr146 and hydrophobic contacts which include interactions with C and C of the proximal histidine His93. The phenol position corresponds to the strongest xenon binding site, Xe1. It …

Proposed Coherent Trapping Of A Population Of Electrons In A C60 Molecule Induced By Laser Excitation, Thomas George, G.P. Zhang

Chemistry & Biochemistry Faculty Works

This Letter demonstrates the possibility of generating coherent population trapping in C60. Similar to a three-level Λ system, C60 has a forbidden transition between the highest occupied molecular orbital (HOMO) (|a⟩) and the lowest unoccupied molecular orbital (LUMO) (|c⟩), but a dipole-allowed transition between HOMO and LUMO+1 (|b⟩) and between |b⟩ and |c⟩. We employ two cw laser fields, one coupling and one probe. The strong coupling field is switched on first to resonantly excite the transition between |b⟩ and |c⟩. After a delay, the probe is switched on; the coherent interaction between the coupling and probe fields traps the …

P21-Activated Kinase-1 Signaling Regulates Transcription Of Tissue Factor And Tissue Factor Pathway Inhibitor., Beatriz Sanchez-Solana, Mona Motwani, Da-Qiang Li, Jeyanthy Eswaran, Rakesh Kumar

Biochemistry and Molecular Medicine Faculty Publications

Tissue factor (TF) is a cell-surface glycoprotein responsible for initiating the coagulation cascade. Besides its role in homeostasis, studies have shown the implication of TF in embryonic development, cancer related events, and inflammation via coagulation-dependent and -independent (signaling) mechanisms. Tissue factor pathway inhibitor (TFPI) plays an important role in regulating TF-initiated blood coagulation. Therefore, transcriptional regulation of TF expression and its physiologic inhibitor TFPI, would allow us to understand the critical step that control many different processes. From a gene profiling study aimed to identify differentially regulated genes between wild type (WT) and p21-activated kinase 1-null (PAK1-KO) mouse embryonic fibroblasts …

Controls Of Nucleosome Positioning In The Human Genome, Daniel J. Gaffney, Graham Mcvicker, Athma A. Pai, Yvonne N. Fondufe-Mittendorf, Noah Lewellen, Katelyn Michelini, Jonathan Widom, Yoav Gilad, Jonathan K. Pritchard

Molecular and Cellular Biochemistry Faculty Publications

Nucleosomes are important for gene regulation because their arrangement on the genome can control which proteins bind to DNA. Currently, few human nucleosomes are thought to be consistently positioned across cells; however, this has been difficult to assess due to the limited resolution of existing data. We performed paired-end sequencing of micrococcal nuclease-digested chromatin (MNase-seq) from seven lymphoblastoid cell lines and mapped over 3.6 billion MNase-seq fragments to the human genome to create the highest-resolution map of nucleosome occupancy to date in a human cell type. In contrast to previous results, we find that most nucleosomes have more consistent positioning …

Targeting Astrocytes Ameliorates Neurologic Changes In A Mouse Model Of Alzheimer's Disease, Jennifer L. Furman, Diana M. Sama, John C. Gant, Tina L. Beckett, M. Paul Murphy, Adam D. Bachstetter, Linda J. Van Eldik, Christopher M. Norris

Pharmacology and Nutritional Sciences Faculty Publications

Astrocytes are the most abundant cell type in the brain and play a critical role in maintaining healthy nervous tissue. In Alzheimer's disease (AD) and most other neurodegenerative disorders, many astrocytes convert to a chronically "activated" phenotype characterized by morphologic and biochemical changes that appear to compromise protective properties and/or promote harmful neuroinflammatory processes. Activated astrocytes emerge early in the course of AD and become increasingly prominent as clinical and pathological symptoms progress, but few studies have tested the potential of astrocyte-targeted therapeutics in an intact animal model of AD. Here, we used adeno-associated virus (AAV) vectors containing the astrocyte-specific …

Mechanism Of Selective Vegf-A Binding By Neuropilin-1 Reveals A Basis For Specific Ligand Inhibition, Matthew W. Parker, Ping Xu, Hou-Fu Guo, Craig W. Vander Kooi

Molecular and Cellular Biochemistry Faculty Publications

Neuropilin (Nrp) receptors function as essential cell surface receptors for the Vascular Endothelial Growth Factor (VEGF) family of proangiogenic cytokines and the semaphorin 3 (Sema3) family of axon guidance molecules. There are two Nrp homologues, Nrp1 and Nrp2, which bind to both overlapping and distinct members of the VEGF and Sema3 family of molecules. Nrp1 specifically binds the VEGF-A_164/5 isoform, which is essential for developmental angiogenesis. We demonstrate that VEGF-A specific binding is governed by Nrp1 residues in the b1 coagulation factor domain surrounding the invariant Nrp C-terminal arginine binding pocket. Further, we show that Sema3F does not display …

The Chemical Origin Of Behavior Is Rooted In Abiogenesis, Brian C. Larson, R. Paul Jensen, Niles Lehman

Chemistry Faculty Publications and Presentations

We describe the initial realization of behavior in the biosphere, which we term behavioral chemistry. If molecules are complex enough to attain a stochastic element to their structural conformation in such as a way as to radically affect their function in a biological (evolvable) setting, then they have the capacity to behave. This circumstance is described here as behavioral chemistry, unique in its definition from the colloquial chemical behavior. This transition between chemical behavior and behavioral chemistry need be explicit when discussing the root cause of behavior, which itself lies squarely at the origins of life and is the foundation …

Molecular Mechanism For Depolarization-Induced Modulation Of Kv Channel Closure, Alain J. Labro, Jerome J. Lacroix, Carlos A. Villalba-Galea, Dirk J. Snyders, Francisco Bezanilla

School of Pharmacy Faculty Articles

Voltage-dependent potassium (Kv) channels provide the repolarizing power that shapes the action potential duration and helps control the firing frequency of neurons. The K(+) permeation through the channel pore is controlled by an intracellularly located bundle-crossing (BC) gate that communicates with the voltage-sensing domains (VSDs). During prolonged membrane depolarizations, most Kv channels display C-type inactivation that halts K(+) conduction through constriction of the K(+) selectivity filter. Besides triggering C-type inactivation, we show that in Shaker and Kv1.2 channels (expressed in Xenopus laevis oocytes), prolonged membrane depolarizations also slow down the kinetics of VSD deactivation and BC gate closure during the …

Cross Regulation Of Sirtuin 1, Ampk, And Ppary In Conjugated Linoleic Acid Treated Adipocytes, Shan Jiang, Wei Wang, Jess Miner, Michael E. Fromm

Department of Biochemistry: Faculty Publications

Trans-10, cis-12 conjugated linoleic acid (t10c12 CLA) reduces triglyceride (TG) levels in adipocytes through multiple pathways, with AMP-activated protein kinase (AMPK) generally facilitating, and peroxisome proliferator-activated receptor γ (PPARγ) generally opposing these reductions. Sirtuin 1 (SIRT1), a histone/protein deacetylase that affects energy homeostasis, often functions coordinately with AMPK, and is capable of binding to PPARγ, thereby inhibiting its activity. This study investigated the role of SIRT1 in the response of 3T3-L1 adipocytes to t10c12 CLA by testing the following hypotheses: 1) SIRT1 is functionally required for robust TG reduction; and 2) SIRT1, …

New Multidetector Solution Could Lead To Safer Alternatives To Faulty Silicone Breast Implants, Judit D. Puskas, Geof Wyatt

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

The article discusses the effort of the University of Akron's Department of Chemical and Biomolecular Engineering to pursue research which aims to reduce or eliminate capsular contracture associated with breast implants. It notes that the new multidetector nanotechnology developed by researchers can be better alternative to silicone gel-filled breast implants. It mentions that the new technology can also help in early diagnosis and imaging of breast cancer.

Haemato Biochemical Alterations In Goats Infected With Coccidiosis, J. Anumol, P. V. Tresamol, K. Vinodkumar, M. R. Saseendranath

Biochemistry Collection

Coccidiosis is an important disease which account for anaemia and associated problems like poor growth rate, suppressed resistance and high mortality in kids. While considering the various etiological factors resulting in anaemia among goats of Kerala, coccidiosis account for about 8 per cent, indicating the significance of adopting proper prevention and control measures against this disease. The present study reveals the severity and depth of anaemic changes induced by coccidia in goats. All the haematological parameters, serum biochemical parameters and serum levels of iron, copper and zinc of coccidiosis infected animals are evaluated statistically by comparing with healthy control animals.

Phylogeny And Evolutionary Patterns In The Dwarf Crayfish Subfamily (Decapoda: Cambarellinae), C. Pedraza-Lara, I. Doadrio, J. Breinholt, Keith A. Crandall

Computational Biology Institute

The Dwarf crayfish or Cambarellinae, is a morphologically singular subfamily of decapod crustaceans that contains only one genus, Cambarellus. Its intriguing distribution, along the river basins of the Gulf Coast of United States (Gulf Group) and into Central México (Mexican Group), has until now lacked of satisfactory explanation. This study provides a comprehensive sampling of most of the extant species of Cambarellus and sheds light on its evolutionary history, systematics and biogeography. We tested the impact of Gulf Group versus Mexican Group geography on rates of cladogenesis using a maximum likelihood framework, testing different models of birth/extinction of lineages. We …

A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver

School of Pharmacy Faculty Articles

In voltage-sensitive phosphatases (VSPs), a transmembrane voltage sensor domain (VSD) controls an intracellular phosphoinositide phosphatase domain, thereby enabling immediate initiation of intracellular signals by membrane depolarization. The existence of such a mechanism in mammals has remained elusive, despite the presence of VSP-homologous proteins in mammalian cells, in particular in sperm precursor cells. Here we demonstrate activation of a human VSP (hVSP1/TPIP) by an intramolecular switch. By engineering a chimeric hVSP1 with enhanced plasma membrane targeting containing the VSD of a prototypic invertebrate VSP, we show that hVSP1 is a phosphoinositide-5-phosphatase whose predominant substrate is PI(4,5)P(2). In the chimera, enzymatic activity …

Phylogenetic Engineering Of The Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Large Subunit In Chlamydomonas Reinhardtii, Boon Hoe Lim

Department of Biochemistry: Dissertations, Theses, and Student Research

Thirty-four residues in the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) may account for the kinetic differences between Rubisco enzyme from green algae and land plants. By substituting these "phylogenetic residues" as groups and combinations of groups in the large subunit of the green alga Chlamydomonas reinhardtii with those of land-plant Rubisco, the functions and relationships of these "phylogenetic groups" were determined.

A phylogenetic-group substitution at the base of catalytic loop 6 of the large subunit decreases the CO₂/O₂ specificity of the enzyme, but function is restored by a further phylogenetic-group substitution at the carboxy-terminal tail. Therefore, these …

Differential Effects Of The Hydrophobic Surfactant Proteins On The Formation Of Inverse Bicontinuous Cubic Phases, Mariya Chavarha, Ryan W. Loney, Kamlesh Kumar, Shankar B. Rananavare, Stephen B. Hall

Chemistry Faculty Publications and Presentations

Prior studies have shown that the biological mixture of the two hydrophobic surfactant proteins, SP-B and SP-C, produces faster adsorption of the surfactant lipids to an air/water interface, and that they induce 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) to form inverse bicontinuous cubic phases. SP-B has a much greater effect than SP-C on adsorption. If the two proteins induce formation of the bicontinuous structures and faster adsorption by similar mechanisms, then they should also have differential ability to form the cubic phases. To test this hypothesis, we measured small angle X-ray scattering on the individual proteins combined with POPE. SP-B replicated the doserelated …