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Title: Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism

Abstract

Sn-glycerol-3-phosphate dehydrogenase (GlpD) is an essential membrane enzyme, functioning at the central junction of respiration, glycolysis, and phospholipid biosynthesis. Its critical role is indicated by the multitiered regulatory mechanisms that stringently controls its expression and function. Once expressed, GlpD activity is regulated through lipid-enzyme interactions in Escherichia coli. Here, we report seven previously undescribed structures of the fully active E. coli GlpD, up to 1.75 {angstrom} resolution. In addition to elucidating the structure of the native enzyme, we have determined the structures of GlpD complexed with substrate analogues phosphoenolpyruvate, glyceric acid 2-phosphate, glyceraldehyde-3-phosphate, and product, dihydroxyacetone phosphate. These structural results reveal conformational states of the enzyme, delineating the residues involved in substrate binding and catalysis at the glycerol-3-phosphate site. Two probable mechanisms for catalyzing the dehydrogenation of glycerol-3-phosphate are envisioned, based on the conformational states of the complexes. To further correlate catalytic dehydrogenation to respiration, we have additionally determined the structures of GlpD bound with ubiquinone analogues menadione and 2-n-heptyl-4-hydroxyquinoline N-oxide, identifying a hydrophobic plateau that is likely the ubiquinone-binding site. These structures illuminate probable mechanisms of catalysis and suggest how GlpD shuttles electrons into the respiratory pathway. Glycerol metabolism has been implicated in insulin signaling and perturbations in glycerolmore » uptake and catabolism are linked to obesity in humans. Homologs of GlpD are found in practically all organisms, from prokaryotes to humans, with >45% consensus protein sequences, signifying that these structural results on the prokaryotic enzyme may be readily applied to the eukaryotic GlpD enzymes.« less

Authors:
; ;  [1]
  1. Pitt
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1006523
Resource Type:
Journal Article
Journal Name:
Proc. Natl. Acad. Sci. USA
Additional Journal Information:
Journal Volume: 105; Journal Issue: (9) ; 03, 2008; Journal ID: ISSN 0027-8424
Country of Publication:
United States
Language:
ENGLISH
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; 59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CATALYSIS; DEHYDROGENATION; ELECTRON TRANSFER; ELECTRONS; ENZYMES; ESCHERICHIA COLI; GLYCERIC ACID; GLYCEROL; GLYCOLYSIS; HUMAN POPULATIONS; MEMBRANES; METABOLIC DISEASES; METABOLISM; OXIDOREDUCTASES; PHOSPHOENOLPYRUVATE; PHOSPHOLIPIDS; RABBIT TUBES; RESPIRATION; SUBSTRATES; UBIQUINONE

Citation Formats

Yeh, Joanne I, Chinte, Unmesh, and Du, Shoucheng. Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism. United States: N. p., 2008. Web. doi:10.1073/pnas.0712331105.
Yeh, Joanne I, Chinte, Unmesh, & Du, Shoucheng. Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism. United States. doi:10.1073/pnas.0712331105.
Yeh, Joanne I, Chinte, Unmesh, and Du, Shoucheng. Wed . "Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism". United States. doi:10.1073/pnas.0712331105.
@article{osti_1006523,
title = {Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism},
author = {Yeh, Joanne I and Chinte, Unmesh and Du, Shoucheng},
abstractNote = {Sn-glycerol-3-phosphate dehydrogenase (GlpD) is an essential membrane enzyme, functioning at the central junction of respiration, glycolysis, and phospholipid biosynthesis. Its critical role is indicated by the multitiered regulatory mechanisms that stringently controls its expression and function. Once expressed, GlpD activity is regulated through lipid-enzyme interactions in Escherichia coli. Here, we report seven previously undescribed structures of the fully active E. coli GlpD, up to 1.75 {angstrom} resolution. In addition to elucidating the structure of the native enzyme, we have determined the structures of GlpD complexed with substrate analogues phosphoenolpyruvate, glyceric acid 2-phosphate, glyceraldehyde-3-phosphate, and product, dihydroxyacetone phosphate. These structural results reveal conformational states of the enzyme, delineating the residues involved in substrate binding and catalysis at the glycerol-3-phosphate site. Two probable mechanisms for catalyzing the dehydrogenation of glycerol-3-phosphate are envisioned, based on the conformational states of the complexes. To further correlate catalytic dehydrogenation to respiration, we have additionally determined the structures of GlpD bound with ubiquinone analogues menadione and 2-n-heptyl-4-hydroxyquinoline N-oxide, identifying a hydrophobic plateau that is likely the ubiquinone-binding site. These structures illuminate probable mechanisms of catalysis and suggest how GlpD shuttles electrons into the respiratory pathway. Glycerol metabolism has been implicated in insulin signaling and perturbations in glycerol uptake and catabolism are linked to obesity in humans. Homologs of GlpD are found in practically all organisms, from prokaryotes to humans, with >45% consensus protein sequences, signifying that these structural results on the prokaryotic enzyme may be readily applied to the eukaryotic GlpD enzymes.},
doi = {10.1073/pnas.0712331105},
journal = {Proc. Natl. Acad. Sci. USA},
issn = {0027-8424},
number = (9) ; 03, 2008,
volume = 105,
place = {United States},
year = {2008},
month = {4}
}