Comparison of metal ‐bound and unbound structures of aminopeptidase B proteins from Escherichia coli and Yersinia pestis

AbstractProtein degradation by aminopeptidases is involved in bacterial responses to stress.Escherichia coli produces two metal ‐dependent M17 family leucine aminopeptidases (LAPs), aminopeptidase A (PepA) and aminopeptidase B (PepB). Several structures have been solved for PepA as well as other bacterial M17 peptidases. Herein, we report the first structures of a PepB M17 peptidase. TheE. coli PepB protein structure was determined at a resolution of 2.05 and 2.6 Å. One structure has both Zn2+ and Mn2+, while the second structure has two Zn2+ ions bound to the active site. A 2.75  Å apo structure is also reported for PepB fromYersinia pestis. Both proteins form homohexamers, similar to the overall arrangement of PepA and other M17 peptidases. However, the divergent N ‐terminal domain in PepB is much larger resulting in a tertiary structure that is more expanded. Modeling of a dipeptide substrate into the C‐terminal LAP domain reveals contacts that account for PepB to uniquely cleave after aspartate.

Source: Protein Science - June 23, 2020 Category: Biochemistry Authors: George Minasov, Matthew R. Lam, Monica Rosas ‐Lemus, Joanna Sławek, Magdalena Woinska, Ivan G. Shabalin, Ludmilla Shuvalova, Bernhard Ø. Palsson, Adam Godzik, Wladek Minor, Karla J. F. Satchell Tags: FULL ‐LENGTH PAPERS Source Type: research