Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/68178
標題: Functional role of a non-active site residue Trp(23) on the enzyme activity of Escherichia coli thioesterase I/protease I/lysophospholipase L-1
作者: Lee, L.C.
Chou, Y.L.
Chen, H.H.
Lee, Y.L.
Shaw, J.F.
關鍵字: Enzyme kinetics
Hydrogen bond
Aromatic-aromatic interaction
Protein
structure
Tryptophan
cavity-creating mutations
amino-acid-residues
protease-i
pi-interactions
tryptophan residue
molecular-cloning
catalytic
center
aromatic rings
lysophospholipase
identification
期刊/報告no:: Biochimica Et Biophysica Acta-Proteins and Proteomics, Volume 1794, Issue 10, Page(s) 1467-1473.
摘要: Escherichia coli possesses a versatile protein with the enzyme activities of thioesterase 1, protease 1, and lysophospholipase L-1. The protein is dubbed as TAP according to the chronological order of gene discovery (TesA/ApeA/PldC). Our previous studies showed that TAP comprises the catalytic triad Ser(10), Asp(154), and His(157) as a charge relay system, as well as Gly(44) and Asn(73) residues devoted to oxyanion hole stabilization. Geometrically, about 10 angstrom away from the enzyme catalytic cleft. Trp(23) showed a stronger resonance shift than the backbone amide resonance observed in the nuclear magnetic resonance (NMR) analyses. In the present work. we conducted site-directed mutagenesis to change Trp into alanine (Ala), phenylalanine (Phe), or tyrosine (Tyr) to unveil the role of the Trp(23) indole ring. Biochemical analyses of the mutant enzymes in combination with TAP's three-dimensional structures suggest that by interlinking the residues participating in this catalytic machinery, Trp(23) could effectively influence substrate binding and the following turnover number. Moreover, it may serve as a contributor to both H-bond and aromatic-aromatic interaction in maintaining the cross-link within the interweaving framework of protein. (C) 2009 Elsevier B.V. All rights reserved.
URI: http://hdl.handle.net/11455/68178
ISSN: 1570-9639
文章連結: http://dx.doi.org/10.1016/j.bbapap.2009.06.008
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