Linked Life Data

15571384

Source:http://linkedlifedata.com/resource/pubmed/id/15571384

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
48
pubmed:dateCreated
2004-12-1
pubmed:abstractText
Malonate semialdehyde decarboxylase (MSAD) is a member of the tautomerase superfamily, a group of structurally homologous proteins that have a characteristic beta-alpha-beta-fold and a catalytic amino-terminal proline. In addition to its physiological decarboxylase activity, the conversion of malonate semialdehyde to acetaldehyde and carbon dioxide, the enzyme has now been found to display a promiscuous hydratase activity, converting 2-oxo-3-pentynoate to acetopyruvate, with a kcat/Km value of 6.0 x 102 M-1 s-1. Pro-1 and Arg-75 are critical for both activities, and the pKa of Pro-1 was determined to be approximately 9.2 by a direct 15N NMR titration. These observations implicate a decarboxylation mechanism in which Pro-1 polarizes the carbonyl oxygen of substrate by hydrogen bonding and/or an electrostatic interaction. Arg-75 may position the carboxylate group into a favorable orientation for decarboxylation. Both the hydratase activity and the pKa value of Pro-1 are shared with trans-3-chloroacrylic acid dehalogenase, another tautomerase superfamily member that precedes MSAD in a bacterial degradation pathway for trans-1,3-dichloropropene. Hence, MSAD and CaaD could have evolved by divergent evolution from a common ancestral protein, retaining the necessary catalytic components for the conjugate addition of water.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15658-9
pubmed:dateRevised
2008-1-17
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
The hydratase activity of malonate semialdehyde decarboxylase: mechanistic and evolutionary implications.
pubmed:affiliation
Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, The University of Texas, Austin, Texas 78712, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't