The role of the active site amino acid residues on the catalytic activity of Cu2Zn2SOD

1993 ◽  
Vol 19 (1-2) ◽  
pp. 193-204 ◽  
Author(s):  
Andrea Scozzafava ◽  
Maria Silvia Viezzoli
2016 ◽  
Vol 60 (10) ◽  
pp. 6084-6090 ◽  
Author(s):  
Dandan He ◽  
Jiachi Chiou ◽  
Zhenling Zeng ◽  
Edward Wai-Chi Chan ◽  
Jian-Hua Liu ◽  
...  

ABSTRACTClinical isolates producing hybrid CTX-M β-lactamases, presumably due to recombination between theblaCTX-M-15andblaCTX-M-14elements, have emerged in recent years. Among the hybrid enzymes, CTX-M-64 and CTX-M-14 display the most significant difference in catalytic activity. This study aims to investigate the mechanisms underlying such differential enzymatic activities in order to provide insight into the structure/function relationship of this class of enzymes. Sequence alignment analysis showed that the major differences between the amino acid composition of CTX-M-64 and CTX-M-14 lie at both the N and C termini of the enzymes. Single or multiple amino acid substitutions introduced into CTX-M-64 and CTX-M-14 were found to produce only minor effects on hydrolytic functions; such a finding is consistent with the notion that the discrepancy between the functional activities of the two enzymes is not the result of only a few amino acid changes but is attributable to interactions between a unique set of amino acid residues in each enzyme. This theory is supported by the results of the thermal stability assay, which confirmed that CTX-M-64 is significantly more stable than CTX-M-14. Our data confirmed that, in addition to the important residues located in the active site, residues distal to the active site also contribute to the catalytic activity of the enzyme through stabilizing its structural integrity.


2012 ◽  
Vol 76 (7) ◽  
pp. 1275-1284 ◽  
Author(s):  
Mitsuki FUKUMOTO ◽  
Daizou KUDOU ◽  
Shouko MURANO ◽  
Tomoo SHIBA ◽  
Dan SATO ◽  
...  

2020 ◽  
Vol 1864 (12) ◽  
pp. 129718
Author(s):  
I.V. Alekseeva ◽  
A.A. Kuznetsova ◽  
A.S. Bakman ◽  
O.S. Fedorova ◽  
N.A. Kuznetsov

RSC Advances ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 5325-5337 ◽  
Author(s):  
Lubna Maryam ◽  
Shamsi Khalid ◽  
Abid Ali ◽  
Asad U. Khan

Mutations of amino acid residues present near active site decrease the catalytic efficiency of beta lactamase enzymes.


2006 ◽  
Vol 188 (10) ◽  
pp. 3614-3621 ◽  
Author(s):  
Anna Rodina ◽  
G. Nigel Godson

ABSTRACT The role of conserved amino acid residues in the polymerase domain of Escherichia coli primase has been studied by mutagenesis. We demonstrate that each of the conserved amino acids Arg146, Arg221, Tyr230, Gly266, and Asp311 is involved in the process of catalysis. Residues Glu265 and Asp309 are also critical because a substitution of each amino acid irreversibly destroys the catalytic activity. Two K229A and M268A mutant primase proteins synthesize only 2-nucleotide products in de novo synthesis reactions under standard conditions. Y267A mutant primase protein synthesizes both full-size and 2-nucleotide RNA, but with no intermediate-size products. From these data we discuss the significant step of the 2-nucleotide primer RNA synthesis by E. coli primase and the role of amino acids Lys229, Tyr267, and Met268 in primase complex stability.


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