A structural study of pig liver glyceraldehyde-3-phosphate dehydrogenase (original) (raw)
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European journal of biochemistry / FEBS, 1971
Maleylation of about four groups per tetramer of NAD-free glyceraldehyde-3-phosphate dehydrogenase or of enzyme -NAD, complex inactivates the enzyme. However, enzyme -NAD, complex is inactivated only by maleylation of about 24 groups per tetramer. This shows that the presence of two moles of the relatively loosely bound coenzyme in addition to the firmly bound ones protects the tetramer against inactivation. Up to the maleybtion of about 12 groups per tetramer NAD-free enzyme, the reactive SH-groups do not react with maleic anhydride. Maleylation of the enzyme -NAD, complex up to the same extent does not affect the Racker band characteristic of the enzymecoenzyme complex and the coenzyme remains firmly bound to the enzyme. However, after maleylation of NAD-free tetrameric enzyme only two NAD molecules can be rebound to the inactive enzyme.
European journal of biochemistry, 1979
The tetrameric glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle binds NAD + and some of its analogues in a negatively cooperative manner, whereas other NAD' analogues bind non-cooperatively to this enzyme. Subsequent to alkylation of a fraction of the active sites of the enzyme with the fluorescent SH reagent N-iodoacetyl-N'-(5-sulfo-1-naphthyl)-ethylenediamine, it was found that the alkylated sites bind NAD' and NAD' analogues with a markedly reduced affinity as compared with non-alkylated sites. It was therefore feasible to measure the fluorescence and the circular polarization of the luminescence of the enzyme-bound alkyl groups as a function of binding of NAD' and of NAD' analogues to the non-alkylated sites. The changes observed indicate that ligand binding to the non-alkylated sites induces changes in the fluorescence properties of the alkyl groups bound to neighbouring subunits, most likely through the protein moiety. The nature of these changes appears to depend on the structure of the coenzyme analogue. The binding of the non-cooperative binders acetyl-pyridineadenine dinucleotide, ATP and ADP-ribose induce different conformational changes in the neighbouring vacant subunit, as monitored by the spectroscopic properties of the bound alkyl group. These results in conjunction with other data support the view that the negative cooperativity in NAD' binding to glyceraldehyde-3-phosphate dehydrogenase results from ligand-induced conformational changes. Furthermore, these results further support the view that subtle structural changes in the coenzyme molecule determine the nature of the conformational changes induced within the enzyme tetramer.
Sequence variability and structure of D-glyceraldehyde-3-phosphate dehydrogenase
The Journal of biological chemistry, 1975
The amino acid sequences of pig muscle and of yeast glyceraldehyde-3-phosphate dehydrogenase are compared with the three-dimensional structure of the lobster muscle enzyme. Residues in sheet and helical regions, on the exterior and interior, in subunit and domain interfaces, as well as residues in the active site have been examined for evolutionary conservation. The residues in the first (NAD binding) domain (1-147) are less conserved than residues in the second (catalytic) domain (148-334) probably because there are fewer internal residues and fewer residues involved in interactions between subunits. Residues in subunit interface are conserved to a significantly greater extent than others, and those involved in catalysis are conserved most of all. Patterns of residues in helices and sheets follow those found for other proteins.