Affiliation:
1. Department of Biology, Plant Science Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
2. Department of Biology, Washington University, St. Louis, Missouri 63130
Abstract
ABSTRACT
Gram-negative bacteria like
Rhodobacter capsulatus
use intertwined pathways to carry out the posttranslational maturation of
c
-type cytochromes (Cyts). This periplasmic process requires at least 10 essential components for apo-Cyt
c
chaperoning, thio-oxidoreduction, and the delivery of heme and its covalent ligation. One of these components, CcmI (also called CycH), is thought to act as an apo-Cyt
c
chaperone. In
R. capsulatus
, CcmI-null mutants are unable to produce
c
-type Cyts and thus sustain photosynthetic (Ps) growth. Previously, we have shown that overproduction of the putative heme ligation components CcmF and CcmH
Rc
(also called Ccl1 and Ccl2) can partially bypass the function of CcmI on minimal, but not on enriched, media. Here, we demonstrate that either additional overproduction of CcmG (also called HelX) or hyperproduction of CcmF-CcmH
Rc
is needed to completely overcome the role of CcmI during the biogenesis of
c
-type Cyts on both minimal and enriched media. These findings indicate that, in the absence of CcmI, interactions between the heme ligation and thioreduction pathways become restricted for sufficient Cyt
c
production. We therefore suggest that CcmI, along with its apo-Cyt chaperoning function, is also critical for the efficacy of holo-Cyt
c
formation, possibly via its close interactions with other components performing the final heme ligation steps during Cyt
c
biogenesis.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
31 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献