ISSN:
1432-2013
Keywords:
Barnacle Central-helix troponin C Contraction Mutagenesis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract. To examine the importance of the central α-helix of troponin C (TnC) we have bacterially expressed one of the isoforms of barnacle TnC (BTnC2), BTnCWT, but without the aspartate residue at position 80 in the central helix (BTnC80–). This manipulation is expected to produce an approximately 100° axial rotation of the C-domain with respect to the N-domain, and a net charge change of –1. BTnC80– mutant was able to restore force to TnC-depleted skinned barnacle myofibrillar bundles to a greater extent than wild-type protein (≅170%). Competition experiments between BTnC80– and BTnC2–4-, a mutant lacking both of the calcium-specific sites (sites II and IV), shows that deletion of a single amino acid in the central helix results in a protein with increased affinity for the thin filament and one that is bound preferentially compared to BTnC2–4- when at equimolar concentrations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004249900133
Permalink
