%A Divya Kapoor
%A Balvinder Singh
%A Subramanian Karthikeyan
%A Purnananda Guptasarma
%O Copyright of this article belongs to Elsevier Science.
%J Enzyme and Microbial Technology
%T A functional comparison of the TET aminopeptidases of P. furiosus and B. subtilis with a protein-engineered variant recombining the former's structure with the latter's active site
%X We have produced and characterized three microbial tetrahedral (TET) aminopeptidases: the previously uncharacterized Bacillus subtilis aminopeptidase (BsuAP), a Pyrococcus furiosus aminopeptidase (PfuAP), and a protein-engineered PfuAP-derived ?designer? aminopeptidase (MutAP) in which the entire active site of PfuAP is replaced with that of BsuAP through the making of 9 non-contiguous structure-guided mutations. The temperature/pH values of optimal function of MutAP (60 ?C/pH 7.0) were found to be comparable to those of its progenitors, BsuAP (70 ?C/pH 7.5) and PfuAP (80 ?C/pH 8.0). The Km of MutAP (3.8 mM) was similar to that of PfuAP (5.0 mM) and unlike that of BsuAP (20.8 mM); however, unlike PfuAP, MutAP showed severe substrate-based inhibition like BsuAP, at substrate exceeding 5 mM concentration. MutAP thus inherits certain characteristics from each of its progenitors. At the same time, the Kcat of MutAP was ?185-fold lower than that of PfuAP and ?300-fold lower than that of BsuAP, indicating an unanticipated slowing down of activity. The results provide tentative evidence that ?structure-guided transplantation? of active sites between proteins can help in recombining enzyme characteristics in interesting and unanticipated ways, to help create novel enzymes.
%N 1
%K Protein engineering; Enzyme engineering; Active site transplantation; Enzyme characterization
%P 1-8
%V 46
%D 2010
%I Elsevier Science
%R doi:10.1016/j.enzmictec.2009.09.003
%L open1120