Substrate Specificity at the P1' Site of Escherichia coli OmpT under Denaturing Conditions(Biochemistry & Molecular Biology)

概要

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Though OmpT has been reported to mainly cleave the peptide bond between consecutive basic amino acids, we identified more precise substrate specificity by using a series of modified substrates, termed PRX fusion proteins, consisting of 184 residues. The cleavage site of the substrate PRR was Arg^<140>-Arg^<141> and the modified substrates PRX substituted all 19 natural amino acids at the P1' site instead of Arg^<141>. OmpT under denaturing conditions (in the presence of 4 M urea) cleaved not only between two consecutive basic amino acids but also at the carboxyl side of Arg^<140> except for the Arg^<140>-Asp^<141>, -Glu^<141>, and -Pro^<141> pairs. In addition to Arg^<140> at the P1 site, similar results were obtained when Lys^<140> was substituted into the P1 site. In the absence of urea, an aspartic acid residue at the P1' site was unfavorable for OmpT cleavage of synthetic decapeptides, the enzyme showed a preference for a dibasic site.
社団法人日本農芸化学会の論文
2002-01-23