Open AccessStructure of RC1339/APRc from Rickettsia conorii , a retropepsin‐like aspartic protease
Author(s) -
Li Mi,
Gustchina Alla,
Cruz Rui,
Simões Marisa,
Curto Pedro,
Martinez Juan,
Faro Carlos,
Simões Isaura,
Wlodawer Alexander
Publication year - 2015
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s1399004715013905
Subject(s) - rickettsia conorii , proteases , dimer , protease , enzyme , aspartic acid , chemistry , monomer , biology , protein quaternary structure , biochemistry , stereochemistry , virology , amino acid , rickettsia , rickettsiosis , gene , virus , organic chemistry , protein subunit , polymer
The crystal structures of two constructs of RC1339/APRc from Rickettsia conorii , consisting of either residues 105–231 or 110–231 followed by a His tag, have been determined in three different crystal forms. As predicted, the fold of a monomer of APRc resembles one‐half of the mandatory homodimer of retroviral pepsin‐like aspartic proteases (retropepsins), but the quaternary structure of the dimer of APRc differs from that of the canonical retropepsins. The observed dimer is most likely an artifact of the expression and/or crystallization conditions since it cannot support the previously reported enzymatic activity of this bacterial aspartic protease. However, the fold of the core of each monomer is very closely related to the fold of retropepsins from a variety of retroviruses and to a single domain of pepsin‐like eukaryotic enzymes, and may represent a putative common ancestor of monomeric and dimeric aspartic proteases.