Biochemistry, Biophysics, and Structural Biology Commons^™

The Atp:Co(I)Rrinoid Adenosyltransferase (Coba) Enzyme Of Salmonella Enterica Requires The 2’-Oh Group Of Atp For Function And Yields Inorganic Triphosphate As Its Reaction Byproduct, Maris V. Fonseca, Nicole R. Baun, Alexander R. Horswill, Ivan Rayment, Jorge C. Escalante-Semerena

Department of Biochemistry: Faculty Publications

The specificity of the ATP:corrinoid adenosyltransferase

(CobA) enzyme of Salmonella enterica serovar

Typhimurium LT2 for its nucleotide substrate was

tested using ATP analogs and alternative nucleotide donors.

The enzyme showed broad specificity for the nucleotide

base and required the 2’-OH group of the ribosyl

moiety of ATP for activity. ³¹P NMR spectroscopy

was used to identify inorganic triphosphate (PPP_i) as

the byproduct of the reaction catalyzed by the CobA

enzyme. Cleavage of triphosphate into pyrophosphate

and orthophosphate did not occur, indicating that

triphosphate cleavage was not required for release of

the adenosylcorrinoid product. Triphosphate was …

Influence Of Protein Tyrosine Kinases On Cell Volume Change-Induced Taurine Release, Herminia Pasantes-Morales, Rodrigo Franco

School of Veterinary and Biomedical Sciences: Faculty Publications

Taurine efflux occurs in association with cell swelling in both hyposmotic and isosmotic conditions and during cell shrinkage in apoptotic death. Release occurs through a leak pathway, is largely Ca²⁺-independent and is sensitive to Cl^– channel blockers. Taurine efflux elicited by hyposmolarity is reduced or suppressed by tyrosine kinase blockers and increased by tyrosine phosphatase inhibitors. The specific kinases involved are still unknown and may be different in the various cell types. Non-receptor and scr-related protein kinases have been identified in some cells as elements that directly phosphorylate the taurine efflux pathway. Possible tyrosine kinase targets are …

Methods And Compositions For Protection Against Bovine Viral Diseases, Subramaniam Srikumaran

School of Veterinary and Biomedical Sciences: Faculty Publications

The present invention relates to methods and compositions for eliciting an immune response against bovine viral epitopes. The methods comprise combining at least one heat shock protein with at least one bovine viral epitope to form a purified epitope/heat shock protein complex and administration of an immune system stimulating amount of the purified epitope/heat shock protein complex. The compositions comprise, a purified epitope/heat shock protein complex comprising at least one bovine viral epitope complexed with at least one heat shock protein, and a pharmaceutically acceptable carrier, diluent or excipient.

Rabd, A Dictyostelium Rab14-Related Gtpase, Regulates Phagocytosis And Homotypic Phagosome And Lysosome Fusion, Ed Harris, James Cardelli

Department of Biochemistry: Faculty Publications

RabD, a Dictyostelium Rab14-related GTPase, localizes in the endo-lysosomal pathway and contractile vacuole system of membranes. Cell lines expressing dominant-negative RabD were defective in endocytosis, endosomal membrane flow and homotypic lysosome fusion. In support of a role for RabD in fusion, cells overexpressing constitutively active RabD^Q67L accumulated enlarged hydrolase-rich acidic vesicles ringed with GFP-RabD, consistent with RabD directly regulating lysosome fusion. To determine whether RabD also regulated phagocytosis and/or homotypic phagosome fusion (a process stimulated by many intracellular pathogens), cells overexpressing dominant-active (RabD^Q67L) or dominant-negative (Rab^N121I) RabD were analyzed microscopically and biochemically. The rate of …

Selenoprotein R Is A Zinc-Containing Stereo-Specific Methionine Sulfoxide Reductase, Gregory V. Kryukov, R. Abhilash Kumar, Ahmet Koc, Zhaohul Sun, Vadim N. Gladyshev

Department of Biochemistry: Faculty Publications

Selenoprotein R (SelR) is a mammalian selenocysteine-containing protein with no known function. Here we report that cysteine homologs of SelR are present in all organisms except certain parasites and hyperthermophiles, and this pattern of occurrence closely matches that of only one protein, peptide methionine sulfoxide reductase (MsrA). Moreover, in several genomes, SelR and MsrA genes are fused or clustered, and their expression patterns suggest a role of both proteins in protection against oxidative stress. Consistent with these computational screens, growth of Saccharomyces cerevisiae SelR and MsrA mutant strains was inhibited, and the strain lacking both genes could not grow, in …

Kinetic Properties Of Bifunctional 6-Phosphofructo-2-Kinase/Fructose-2,6-Bisphosphatase From Spinach Leaves, Jennifer E. Markham, Nicholas J. Kruger

Department of Biochemistry: Faculty Publications

A cDNA encoding 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was isolated from a Spinacia oleracea leaf library and used to ex­press a recombinant enzyme in Escherichia coli and Spodoptera frugiperda cells. The insoluble protein expressed in E. coli was purified and used to raise antibodies. Western blot analysis of a protein extract from spinach leaf showed a single band of 90.8 kDa. Soluble protein was purified to homogeneity from S. frugiperda cells infected with recombinant baculovirus harboring the isolated cDNA. The soluble protein had a molecular mass of 320 kDa, estimated by gel filtration chromatography, and a subunit size of 90.8 kDa. The purified pro­tein …

Identification And Analysis Of A Conserved Immunoglobulin E-Binding Epitope In Soybean G1a And G2a And Peanut Ara H 3 Glycinins, Ping Ziang, Tom A. Beardslee, Michael G. Zeece, John P. Markwell, Gautam Sarath

Gautam Sarath Publications

To identify conserved immunoglobulin E (IgE)-binding epitopes among legume glycinins, we utilized recombinant soybean G2a and G2a-derived polypeptide fragments.

Purification And Characterization Of Acylation Stimulating Protein From Porcine Serum, Hong Zhang, Sheila K. Jacobi, Candace F. Toombs, Katherine H. Cianflone, Natalya Nersesian, Gautam Sarath, Jess L. Miner

Gautam Sarath Publications

A method for purifying acylation stimulating protein (ASP) from porcine serum is described. The mRNA encoding ASP was cloned by reverse transcriptase-polymerase chain reaction which predicted a 76 residue peptide. Based on this sequence, we generated antisera to a C-terminal peptide (ASP_1–20) which aided ASP purification. Identity of the purified protein was verified by N-terminal sequencing. The molecular mass of porcine ASP is 8926. Porcine ASP stimulated esterification of fatty acid into triacylglycerol in cultured human cells with potency similar to that of human ASP (twofold at 5 μM). Based on this evidence that ASP exists in porcine …

Ultrasound Based Quantitative Motion Measurement Using Speckle Size Estimation, James D. Hamilton, Larry Y. L. Mo, Gregory R. Bashford

Biomedical Imaging and Biosignal Analysis Laboratory

An ultrasound system determines the relative movement in a first direction (F1) of first matter, such as blood flow, and second matter, such as an artery wall, in a subject under study (S). A beam (B1) of ultrasound waves defining a plurality of beam positions (BP1 and BP2) and beam axes (A1 and A2) are moved in scan direction having components parallel to direction F1. First and second blocks of data representing the first and second matter, respectively, are generated. A processor (20) performs an estimation of speckle size on first data to obtain a first result, and performs analysis …

Transitions In Histone Acetylation Reveal Boundaries Of Three Separately Regulated Neighboring Loci, Michael D. Litt, Melanie A. Simpson, Felix Recillas-Targa, Marie-Noelle Prioleau, Gary Felsenfeld

Department of Biochemistry: Faculty Publications

We have studied developmentally regulated patterns of histone acetylation at high resolution across ~54 kb of DNA containing three independently regulated but neighboring genetic loci. These include a folate receptor gene, a 16 kb condensed chromatin region, the chicken β-globin domain and an adjacent olfactory receptor gene. Within these regions the relative levels of acetylation appear to fall into three classes. The condensed chromatin region maintains the lowest acetylation at every developmental stage. Genes that are inactive show similarly low levels, but activation results in a dramatic increase in acetylation. The highest levels of acetylation are seen at regulatory sites …

Correlation Between Histone Lysine Methylation And Developmental Changes At The Chicken Β-Globin Locus, Michael D. Litt, Melanie A. Simpson, Miklos Gaszner, D. David Allis, Gary Felsenfeld

Department of Biochemistry: Faculty Publications

Methylation of histones at specific residues plays an important role in transcriptional regulation. Chromatin immunoprecipitation of dimethylated lysine 9 on histone H3 across 53 kilobases of the chicken β-globin locus during erythropoiesis shows an almost complete anticorrelation between regions of elevated lysine 9 methylation and acetylation. Lysine 9 is methylated most over constitutive condensed chromatin and developmentally inactive globin genes. In contrast, lysine 4 methylation of histone H3 correlates with H3 acetylation. These results lead us to propose a mechanism by which the insulator in the β-globin locus can protect the globin genes from being silenced by adjacent condensed chromatin.

Selenium Metabolism In Drosophila, F. Javier Martin-Romero, Gregory V. Kryukov, Alexei V. Lobanov, Bradley A. Carlson, Byeong Jae Lee, Vadim N. Gladyshev, Dolph L. Hatfield

Vadim Gladyshev Publications

Selenocysteine is a rare amino acid in protein that is encoded by UGA with the requirement of a downstream mRNA stem-loop structure, the selenocysteine insertion sequence element. To detect selenoproteins in Drosophila, the entire genome was analyzed with a novel program that searches for selenocysteine insertion sequence elements, followed by selenoprotein gene signature analyses. This computational screen and subsequent metabolic labeling with ⁷⁵Se and characterization of selenoprotein mRNA expression resulted in identification of three selenoproteins: selenophosphate synthetase 2 and novel G-rich and BthD selenoproteins that had no homology to known proteins. To assess a biological role for these …

Identification And Characterization Of A New Mammalian Glutaredoxin (Thioltransferase), Grx2, Vadim N. Gladyshev, Aimin Liu, Sergey V. Novoselov, Konstantin Krysan, Qi-An Sun, Valentin M. Kryukov, Gregory V. Kryukov, Marjorie F. Lou

Vadim Gladyshev Publications

A thiol/disulfide oxidoreductase component of the GSH system, glutaredoxin (Grx), is involved in the reduction of GSH-based mixed disulfides and participates in a variety of cellular redox pathways. A single cytosolic Grx (Grx1) was previously described in mammals. We now report identification and characterization of a second mammalian Grx, designated Grx2. Grx2 exhibited 36% identity with Grx1 and had a disulfide active center containing the Cys-Ser-Tyr-Cys motif. Grx2 was encoded in the genomes of mammals and birds and expressed in a variety of cell types. The gene for human Grx2 consisted of four exons and three introns, spanned 10 kilobase …

Reversible Phosphorylation Of Photosynthetic Pep Carboxylase: Studies On C4-Leaf Pp2a And Recombinant Pepc-Kinase From Cam-Induced Mesembryanthemum Crystallinum, L. Dong, N. V. Ermolova, M. A. Cushman, T. Taybi, J. C. Cushman, Raymond Chollet

Department of Biochemistry: Faculty Publications

The activity and allosteric properties of plant PEPC are controlled posttranslationally by specific reversible phosphorylation of a strictly conserved Ser residue near the N-terminus. This up/down-modulation is catalyzed by a transcriptionally regulated, seemingly dedicated Ser/Thr kinase (PpcK) and an opposing Ser/Thr phosphatase (PP2A). We have now partially purified and characterized the native form of this largely “neglected” PP2A from maize leaves using various chromatographic and affinity matrices, and C₄ [³²P]PEPC as substrate (Dong et al., 2001, Planta [in press]). The results indicate that the C₄-leaf holoenzyme is analogous to yeast and mammalian PP2As in regards …

Unexpected Post-Translational Modifications And Novel Sequence-Structure Relationships Revealed By The Crystal Structure Of Chlamydomonas Reinhardtii Rubisco, T. C. Taylor, A. Backlund, R. J. Spreitzer, I. Andersson

Department of Biochemistry: Faculty Publications

The crystal structure of Rubisco from Chlamydomonas reinhardtii has been solved to 1.4 Å resolution. In addition to clear electron density for the carbamate on lys-201, the active site magnesium ion and the inhibitor 2-CABP, there was unexpected but unambiguous electron density for further specific post-translational modification. The N-terminus of the mature small subunit is methylated. The large subunit contains two methylcysteine residues (256 & 369) and two hydroxyproline residues (104 & 151). The small subunit from Chlamydomonas shows a structure more similar to that of the higher green plants than that from other algae of known structure. An extensive …

Can Negligible Levels Of Rubisco Activase, Be The Reason For Decreased Rubisco Activity Levels In Guard Cells?, S. Madhavan, P. Echtenkamp

Department of Biochemistry: Faculty Publications

Rubisco in guard cell chloroplasts has been a subject of controversy for decades. Several studies have unequivocally confirmed not only the presence of Rubisco in guard cells but also found it to be catalytically active. Based on a cell basis, the amount of Rubisco in guard cells is suggested to be in the range of 0.6 to 1.4 % whereas its activity is reported to be in the range of 0.35 to 0.5%, of a mesophyll cell. This low activity may be due a) to a low Rubisco content, and/or, b) to either the absence or an inactive functional activation …

Nonsymbiotic Hemoglobins In Rice Are Synthesized During Germination And In Differentiating Cell Types, E. J. H. Ross, L. Shearman, M. Mathiesen, Y.J. Zhou, R. Arredondo-Peter, Gautam Sarath, R. V. Klucas

Gautam Sarath Publications

Nonsymbiotic hemoglobins (ns-Hbs) previously have been found in monocots and dicots; however, very little is known about the tissue and cell type localization as well as the physiological function(s) of these oxygen-binding proteins. We report the immunodetection and immunolocalization of ns-Hbs in rice (Oryza sativa L.) by Western blotting and in situ confocal laser scanning techniques. Ns-Hbs were detected in soluble extracts of different tissues from the developing rice seedling by immunoblotting. Levels of ns-Hbs increased in the germinating seed for the first six days following imbibition and remained relatively constant thereafter. In contrast, ns-Hb levels decreased during leaf …

Selective Inhibition Of Selenocysteine Trna Maturation And Selenoprotein Synthesis In Transgenic Mice Expressing Isopentenyladenosine-Deficient Selenocysteine Trna, Mohamed E. Moustafa, Bradley A. Carlson, Muhammed A. El-Saadani, Gregory V. Kryukov, Qi-An Sun, John W. Harney, Kristina E. Hill, Gerald F. Combs, Lionel Feigenbaum, David B. Mansur, Raymond F. Burk, Marla J. Berry, Alan M. Diamond, Byeong Jae Lee, Vadim Gladyshev, Dolph A. Hatfield

Vadim Gladyshev Publications

Selenocysteine (Sec) tRNA (tRNA ^[Ser]Sec) serves as both the site of Sec biosynthesis and the adapter molecule for donation of this amino acid to protein. The consequences on selenoprotein biosynthesis of overexpressing either the wild type or a mutant tRNA ^[Ser]Sec lacking the modified base, isopentenyladenosine, in its anticodon loop were examined by introducing multiple copies of the corresponding tRNA ^[Ser]Sec genes into the mouse genome. Overexpression of wild-type tRNA ^[Ser]Sec did not affect selenoprotein synthesis. In contrast, the levels of numerous selenoproteins decreased in mice expressing isopentenyladenosine-deficient (i⁶A^-) tRNA ^[Ser]Sec in a protein- and …

Chapter 13. The 15 Kda Selenoprotein (Sepl5): Functional Studies And A Role In Cancer Etiology, Vadim Gladyshev, Alan M. Diamond, Dolph L. Hatfield

Vadim Gladyshev Publications

The 15 kDa selenoprotein (Sepl5) is one of several recently identified selenoproteins. It contains a single selenocysteine residue in the middle of a 162-amino acid open reading frame and has no detectable homology to known proteins. The human Sepl5 gene spans 5 1 kb, has 5 exons and is located on chromosome 1 at position p3 1. The gene contains two single nucleotide polymorphisms in the 3'-untranslated region (3'-UTR) including one in the SECIS element, that are distributed differently between Caucasians and African Americans. Sep15 localizes to the endoplasmic reticulum where it is tightly bound to UDP-glucose:glycoprotein glucosyltransferase, a protein …

Chapter 25. Selenium In Biology And Human Health: Controversies And Perspectives, Vadim Gladyshev

Vadim Gladyshev Publications

Important unresolved questions raised by the contributors of this book and addressing roles of selenium in biology and human health are discussed. Resolving major scientific controversies in the field should further highlight a bright future for selenium in fundamental science, biotechnology and medicine.

Association Between The 15-Kda Selenoprotein And Udp-Glucose:Glycoprotein Glucosyltransferase In The Endoplasmic Reticulum Of Mammalian Cells, Konstantin V. Korotkov, Easwari Kumaraswamy, You Zhou, Dolph L. Hatfield, Vadim N. Gladyshev

Vadim Gladyshev Publications

Mammalian selenocysteine-containing proteins characterized with respect to function are involved in redox processes and exhibit distinct expression patterns and cellular locations. A recently identified 15-kDa selenoprotein (Sep15) has no homology to previously characterized proteins, and its function is not known. Here we report the intracellular localization and identification of a binding partner for this selenoprotein which implicate Sep15 in the regulation of protein folding. The native Sep15 isolated from rat prostate and mouse liver occurred in a complex with a 150-kDa protein. The latter protein was identified as UDP-glucose:glycoprotein glucosyltransferase (UGTR), the endoplasmic reticulum (ER)-resident protein, which was previously shown …

Evidence For Two Mechanisms Of Amino Acid Osmolyte Release From Hippocampal Slices, R. Franco, M. E. Torres-Marquez, H. Pasantes-Morales

School of Veterinary and Biomedical Sciences: Faculty Publications

A 30% decrease in osmolarity stimulated ³H-taurine, ³H-GABA and glutamate (followed as ³H-D-aspartate) efflux from rat hippocampal slices. ³H-taurine efflux was activated rapidly but inactivated slowly. It was decreased markedly by 100 μM 5-nitro-(3-phenylpropylamino) benzoic acid (NPPB) and 600 μM niflumic acid and inhibited strongly by tyrphostins AG18, AG879 and AG112 (25–100 μM), suggesting a tyrosine kinase-mediated mechanism. Hyposmolarity activated the mitogen-activated protein kinases (MAPK) extracellular-signal-related kinase-1/2 (ERK1/ERK2) and p38, but blockade of this reaction did not affect ³H-taurine efflux. Hyposmosis also activated phosphatidyl-inositide 3-kinase (PI3K) and its prevention by wortmannin (100 nM) essentially abolished …

Heterogeneity Within Animal Thioredoxin Reductases, Qi-An Sun, Francesca Zappacosta, Valentina M. Factor, Peter J. Wirth, Dolph L. Hatfield, Vadim N. Gladyshev

Vadim Gladyshev Publications

Animal thioredoxin reductases (TRs) are selenocysteine- containing flavoenzymes that utilize NADPH for reduction of thioredoxins and other protein and nonprotein substrates. Three types of mammalian TRs are known, with TR1 being a cytosolic enzyme, and TR3, a mitochondrial enzyme. Previously characterized TR1 and TR3 occurred as homodimers of 55–57-kDa subunits. We report here that TR1 isolated from mouse liver, mouse liver tumor, and a human T-cell line exhibited extensive heterogeneity as detected by electrophoretic, immunoblot, and mass spectrometry analyses. In particular, a 67-kDa band of TR1 was detected. Furthermore, a novel form of mouse TR1 cDNA encoding a 67-kDa selenoprotein …

Cloning And Expression Analysis Of Hemoglobin Genes From Maize (Zea Mays Ssp. Mays) And Teosinte (Zea Mays Ssp. Parviglumis), Elena Aréchaga-Ocampo, Juan Saenz-Rivera, Gautam Sarath, Robert V. Klucas, Raúl Arredondo-Peter

Gautam Sarath Publications

With the exception of barley and rice, little is known about the existence of hemoglobins (Hbs) in cereals. This work reports the cloning and analysis of hb genes from maize (Zea mays ssp. mays) and teosinte (Zea mays ssp. parviglumis). Coding sequences of maize and teosinte hb genes (hbm and hbt, respectively) are highly similar to each other and are interrupted by three introns located at identical positions as other plant hb genes. Sequences of predicted Hbm and Hbt proteins are identical. The hydropathic profile of Hbm and Hbt is highly similar to that …

Monoclonal Light Chain–Mesangial Cell Interactions: Early Signaling Events And Subsequent Pathologic Effects, William J. Russell, James Cardelli, Ed Harris, R. John Baier, Guillermo A. Herrera

Department of Biochemistry: Faculty Publications

Glomerulopathic monoclonal light chains (G-LC) interact with mesangial cells (MC), resulting in alterations of mesangial homeostasis. Early signaling events control mitogenic activities and cytokine production, which in turn participate in the subsequent pathologic events. Mesangial homeostasis is affected in two very different ways, depending on whether the G-LC is from a patient with light chain deposition disease (LCDD) or light chain–related amyloidosis (AL-Am). In contrast, tubulopathic (T)-LC chains from patients with myeloma cast nephropathy do not significantly interact with MC and result in no alterations in mesangial homeostasis. Therefore, understanding early events in the monoclonal LC–MC interactions is fundamental. MC …

The Wasp-Like Protein Scar Regulates Macropinocytosis, Phagocytosis And Endosomal Membrane Flow In Dictyostelium, David J. Seastone, Ed Harris, Lesly A. Temesvari, James E. Bear, Charles L. Saxe, James Cardelli

Department of Biochemistry: Faculty Publications

Scar, a member of the WASp protein family, was discovered in Dictyostelium discoideum during a genetic screen for second-site mutations that suppressed a developmental defect. Disruption of the scar gene reduced the levels of cellular F-actin by 50%. To investigate the role of Scar in endocytosis, phagocytosis and endocytic membrane trafficking, processes that depend on actin polymerization, we have analyzed a Dictyostelium cell line that is genetically null for Scar. Rates of fluid phase macropinocytosis and phagocytosis are significantly reduced in the scar^- cell-line. In addition, exocytosis of fluid phase is delayed in these cells and movement of fluid …

Rab11-Like Gtpase Associates With And Regulates The Structure And Function Of The Contractile Vacuole System In Dictyostelium, Ed Harris, Kunito Yoshida, James Cardelli, John Bush

Department of Biochemistry: Faculty Publications

Screening of a cDNA library revealed the existence of a Dictyostelium cDNA encoding a protein 80% identical at the amino acid level to mammalian Rab11. Subcellular fractionation and immunofluorescence studies revealed that DdRab11 was exclusively associated with the ATPase proton pump-rich contractile vacuole membrane system, consisting of a reticular network and bladder-like vacuoles. Video microscopy of cells expressing GFP-DdRab11 revealed that this Rab was associated with contractile vacuolar bladders undergoing formation, fusion and expulsion of water. The association of DdRab11 with contractile vacuole membranes was disrupted when cells were exposed to either hypo-osmotic conditions or an inhibitor of the ATPase …

Selenoprotein Oxidoreductase With Specificity For Thioredoxin And Glutathione Systems, Qi-An Sun, Leo Kirnarsky, Simon Sherman, Vadim N. Gladyshev

Department of Biochemistry: Faculty Publications

Thioredoxin (Trx) and glutathione (GSH) systems are considered to be two major redox systems in animal cells. They are reduced by NADPH via Trx reductase (TR) or oxidized GSH (GSSG) reductase and further supply electrons for deoxyribonucleotide synthesis, antioxidant defense, and redox regulation of signal transduction, transcription, cell growth, and apoptosis. We cloned and characterized a pyridine nucleotide disulfide oxidoreductase, Trx and GSSG reductase (TGR), that exhibits specificity for both redox systems. This enzyme contains a selenocysteine residue encoded by the TGA codon. TGR can reduce Trx, GSSG, and a GSH-linked disulfide in in vitro assays. This unusual substrate specificity …

The Cia5 Gene Controls Formation Of The Carbon Concentrating Mechanism In Chlamydomonas Reinhardtii, Youbin Xiang, Jun Zhang, Donald P. Weeks

Department of Biochemistry: Faculty Publications

Wild-type Chlamydomonas reinhardtii cells shifted from high concentrations (5%) of CO2 to low, ambient levels (0.03%) rapidly increase transcription of mRNAs from several CO₂-responsive genes. Simultaneously, they develop a functional carbon concentrating mechanism that allows the cells to greatly increase internal levels of CO₂ and HCO₃. The cia5 mutant is defective in all of these phenotypes. A newly isolated gene, designated Cia5, restores transformed cia5 cells to the phenotype of wild-type cells. The 6,481-bp gene produces a 5.1-kb mRNA that is present constitutively in light in high and low CO₂ both in …

C3 Origins Of The C4 Pathway Regulatory Enzyme, Ppdk-Rp, C. J. Chastain, Gautam Sarath, Raymond Chollet

Gautam Sarath Publications

A current view of C₄ and CAM evolution holds that all of the constituent enzymes of the C₄ pathway preexisted in C₃ plants, albeit functioning in nonphotosynthetic capacities.