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Coordination of functions by proline metabolic proteins.

脯氨酸代谢蛋白的功能协调。

基本信息

批准号：
9115668
负责人：
JOHN J TANNER
金额：
$ 28.05万
依托单位：
UNIVERSITY OF MISSOURI-COLUMBIA
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-05-05 至 2019-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9115668
关键词：
Active Sites Amino Acids Awareness Bacteria Biological Book Chapters C-terminal Catabolism Cells Cellular Structures Citric Acid Cycle Communication Complex Crystallography Defect Deposition Disease Electron Transport Electrons Enzymatic Biochemistry Enzymes Eukaryota Evolution Exhibits Family Funding Genus Mycobacterium Glutamates Health Heart Helicobacter Human Hydrolysis Kinetics Knowledge Link Longevity Medical Membrane Proteins Metabolic Metabolic Diseases Metabolic Pathway Metabolism Modeling Molecular Organism Oxidoreductase Pathway interactions Phase Predisposition Production Proline Proline Dehydrogenase Property Proteins Publishing Reaction Reporting Research Roentgen Rays Role Scheme Schizophrenia Speed Structure System Time Tumor Suppression Virulence Virulence Factors Work abstracting aldehyde dehydrogenases alpha ketoglutarate base carbon skeleton carboxylate design enzyme substrate in vivo interest journal article member metabolic engineering molecular dynamics novel oxidation pathogen polypeptide prevent protein protein interaction pyrroline scaffold structural biology systems research

项目摘要

DESCRIPTION (provided by applicant): Metabolic enzymes in cells rarely function in isolation. Often their activities are coordinated by physical association with each other and cellular structures. A consequence of these associations is that metabolic intermediates do not equilibrate with the cellular milieu but rather are channeled between enzymes. Despite the widespread recognition that protein-protein interactions are ubiquitous, the mechanisms of substrate channeling remain relatively understudied and thus poorly understood. We help close this knowledge gap by exploring substrate channeling within and between the enzymes of proline catabolism. Proline catabolism comprises two enzymes and an intervening hydrolysis step. The flavoenzyme proline dehydrogenase (PRODH) catalyzes the oxidization of L-proline to 1-pyrroline-5-carboxylate (P5C). Hydrolysis of P5C yields L-glutamate--semialdehyde, which is oxidized to L-glutamate by the NAD+-dependent enzyme P5C dehydrogenase (P5CDH). These enzymes have been implicated in many aspects of human health and disease, including tumor suppression, hyperprolinemia metabolic disorders, schizophrenia susceptibility, life- span extension, and the virulence of fungal and bacterial pathogens. In some organisms, PRODH and P5CDH are combined into a single polypeptide chain known as proline utilization A (PutA). The packaging of sequential enzymes from a metabolic pathway into a single protein not only implies substrate channeling but also the possibility of protein-protein interactions between the monofunctional enzymes. Thus, proline catabolism affords an excellent opportunity to compare substrate channeling within and between enzymes. The next phase of this project builds upon three major accomplishments made during the previous funding cycle: determination of the first crystal structures of PutA proteins, discovery of a novel hysteretic substrate channeling kinetic mechanism, and uncovering the first evidence for inter-enzyme substrate channeling between monofunctional PRODH and P5CDH enzymes. The specific aims are to (1) elucidate the diverse structural solutions to substrate channeling that have evolved in the PutA family, (2) determine the structural basis and conservation of the hysteretic channeling mechanism, and (3) study substrate channeling in biological context by examining PRODH - P5CDH interactions in whole cells and determining the phenotypic consequences of disrupting proline metabolic channeling.