Publication Date:
1990-08-31
Description:
The isocitrate dehydrogenase of Escherichia coli is an example of a ubiquitous class of enzymes that are regulated by covalent modification. In the three-dimensional structure of the enzyme-substrate complex, isocitrate forms a hydrogen bond with Ser113, the site of regulatory phosphorylation. The structures of Asp113 and Glu113 mutants, which mimic the inactivation of the enzyme by phosphorylation, show minimal conformational changes from wild type, as in the phosphorylated enzyme. Calculations based on observed structures suggest that the change in electrostatic potential when a negative charge is introduced either by phosporylation or site-directed mutagenesis is sufficient to inactivate the enzyme. Thus, direct interaction at a ligand binding site is an alternative mechanism to induced conformational changes from an allosteric site in the regulation of protein activity by phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hurley, J H -- Dean, A M -- Sohl, J L -- Koshland, D E Jr -- Stroud, R M -- GM 24485/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 31;249(4972):1012-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2204109" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Binding Sites
;
Escherichia coli/*enzymology/genetics
;
Homeostasis
;
Isocitrate Dehydrogenase/genetics/*metabolism
;
Models, Molecular
;
Molecular Sequence Data
;
Phosphorylation
;
Protein Conformation
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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