A Caltech Library Service

Open-State Disulfide Crosslinking between Mycobacterium tuberculosis Mechanosensitive Channel Subunits

Shapovalov, George and Bass, Randal and Rees, Douglas C. and Lester, Henry A. (2003) Open-State Disulfide Crosslinking between Mycobacterium tuberculosis Mechanosensitive Channel Subunits. Biophysical Journal, 84 (4). pp. 2357-2365. ISSN 0006-3495. PMCID PMC1302802.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


The mechanosensitive channel of large conductance from Mycobacterium tuberculosis (Tb-MscL) was subjected to cysteine-scanning mutagenesis at several residues in the M1 region. The V15C channel displayed disulfide crosslinking in air, but not in the presence of 100 mM β-mercaptoethanol. In single-channel experiments, the V15C channel was more sensitive to tension than was wild-type Tb-MscL. In air, Tb-MscL V15C occasionally displayed signature-events: at constant tension, there was first a sojourn in the highest conductance open state, then a series of transitions to substates. During a signature-event, these transitions do not appear to be reversible. Some sojourns in the lower conductance states lasted for ≥100 s. These signature-events were abolished by 100 mM β-mercaptoethanol and did not occur in a cysteineless gain-of-function mutant, suggesting that the signature-events represent disulfide crosslinking between channel subunits. We conclude that the crosslinking occurs during an open state during asymmetric sojourns that bring the α-carbons of adjacent 15C side chains within 3.6–6.8 Å. Such asymmetric structures must be considered in models of TB-MscL gating.

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
Rees, Douglas C.0000-0003-4073-1185
Lester, Henry A.0000-0002-5470-5255
Contact Email
Additional Information:© 2003 by the Biophysical Society. Submitted August 30, 2002, and accepted for publication December 9, 2002. We thank Sergei Sukharev and Paul Blount for introducing us to MscL electrophysiology, Josh Maurer for mutants and cells, and Ido Braslavsky, Donald Elmore, Steve Quake, Gerd Kochendoerfer, and Dennis Dougherty for valuable discussion. This research was supported by a grant from the National Institutes of Health (GM-062532), by a Burroughs-Wellcome Fund Computation and Molecular Biology Fellowship to George Shapovalov, and by an National Research Service Award to Randal Bass (GM-020705).
Funding AgencyGrant Number
Burroughs-Wellcome FundUNSPECIFIED
Issue or Number:4
PubMed Central ID:PMC1302802
Record Number:CaltechAUTHORS:20141212-145345633
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52788
Deposited By: SWORD User
Deposited On:22 Dec 2014 20:00
Last Modified:03 Oct 2019 07:44

Repository Staff Only: item control page