The Periplasmic Loop Provides Stability to the Open State of the CorA Magnesium Channel
2012 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 287, no 33, 27547-27555 p.Article in journal (Refereed) Published
Crystal structures of the CorA Mg2+ channel have suggested that metal binding in the cytoplasmic domain stabilizes the pentamer in a closed conformation. The open metal free state of the channel is, however, still structurally uncharacterized. Here, we have attempted to map conformational states of CorA from Thermotoga maritima by determining which residues support the pentameric structure in the presence or absence of Mg2+. We find that when Mg2+ is present, the pentamer is stabilized by the putative gating sites (M1/M2) in the cytoplasmic domain. Strikingly however, we find that the conserved and functionally important periplasmic loop is vital for the integrity of the pentamer when Mg2+ is absent from the M1/M2 sites. Thus, although the periplasmic loops were largely disordered in the x-ray structures of the closed channel, our data suggests a prominent role for the loops in stabilizing the open conformation of the CorA channels.
Place, publisher, year, edition, pages
2012. Vol. 287, no 33, 27547-27555 p.
Biochemistry and Molecular Biology
Research subject Biochemistry
IdentifiersURN: urn:nbn:se:su:diva-82951DOI: 10.1074/jbc.M112.371484ISI: 000307840700030OAI: oai:DiVA.org:su-82951DiVA: diva2:576920