Affordable Access

deepdyve-link
Publisher Website

Discovery of posttranslational maturation by self-subunit swapping.

Authors
  • Zhou, Zhemin
  • Hashimoto, Yoshiteru
  • Shiraki, Kentaro
  • Kobayashi, Michihiko
Type
Published Article
Journal
Proceedings of the National Academy of Sciences
Publisher
Proceedings of the National Academy of Sciences
Publication Date
Sep 30, 2008
Volume
105
Issue
39
Pages
14849–14854
Identifiers
DOI: 10.1073/pnas.0803428105
PMID: 18809911
Source
Medline
License
Unknown

Abstract

Several general mechanisms of metallocenter biosynthesis have been reported and reviewed, and in all cases, the components or subunits of an apoprotein remain in the final holoprotein. Here, we first discovered that one subunit of an apoenzyme did not remain in the functional holoenzyme. The cobalt-containing low-molecular-mass nitrile hydratase (L-NHase) of Rhodococcus rhodochrous J1 consists of beta- and alpha-subunits encoded by the nhlBA genes, respectively. An ORF, nhlE, just downstream of nhlBA, was found to be necessary for L-NHase activation. In contrast to the cobalt-containing L-NHase (holo-L-NHase containing Cys-SO(2)(-) and Cys-SO(-) metal ligands) derived from nhlBAE, the gene products derived from nhlBA were cobalt-free L-NHase (apo-L-NHase lacking oxidized cysteine residues). We discovered an L-NHase maturation mediator, NhlAE, consisting of NhlE and the cobalt- and oxidized cysteine-containing alpha-subunit of L-NHase. The incorporation of cobalt into L-NHase was shown to depend on the exchange of the nonmodified cobalt-free alpha-subunit of apo-L-NHase with the cobalt-containing cysteine-modified alpha-subunit of NhlAE. This is a posttranslational maturation process different from general mechanisms of metallocenter biosynthesis known so far: the unexpected behavior of a protein in a protein complex, which we named "self-subunit swapping."

Report this publication

Statistics

Seen <100 times