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Myofibrillar tightly bound calcium in skeletal muscle fibers: a possible role of this cation in titin strands aggregation
Author(s) -
Coulis Gerald,
Sentandreu Miguel A,
Bleimling Nathalie,
Gautel Mathias,
Benyamin Yves,
Ouali Ahmed
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01436-4
Subject(s) - titin , sarcomere , myofibril , calcium , biophysics , obscurin , chemistry , tetramer , protein filament , biochemistry , myocyte , microbiology and biotechnology , biology , organic chemistry , enzyme
In muscle cells, part of the calcium is tightly bound to the N1‐ and N2‐line of the sarcomere but its physiological significance was unknown. In the present work we reported the ability of a recombinant titin fragment spanning titin domains Z9 to I1 to tightly bind calcium ions with a K d of 0.049±0.004 nM. We further showed that calcium induced a spontaneous aggregation of the titin fragment and that the major aggregate is a tetramer. The implication of these findings on the organization of the six titin strands that emanate from the end of the thick filament within the I‐band is discussed.