New subfragment 1 of skeletal muscle myosin obtained by thrombin cleavage.
The head of the myosin molecule (i.e., subfragment 1 with a heavy chain of 95 kDa) is usually obtained by chymotryptic cleavage in the presence of a divalent cation chelator. In the present work, we used another specific proteolytic enzyme, thrombin, to produce a limited cut within the myosin molecule, resulting in a new species of N-terminal fragment. Treatment of skeletal muscle myosin yielded a 97-kDa split heavy chain associated with intact light chains, corresponding to a single cut. The ATPase activities of this new S-1 derivative were slightly affected by the breakdown. It recognized actin in an ATP-dependent manner, as expected, with an affinity 2-5 times higher than that of the usual chymotryptic S-1 preparation but with a very different electron microscopic pattern. Functional differences are noted, and we involve them more precisely in relation to possible structural aspects of the additional C-terminal segment extending the usual S-1 heavy chain from 95 to 97 kDa.
Bonet-Kerrache
A
A
Centre de Recherches de Biochimie Macromoléculaire CNRS, INSERM U 249, Université Montpellier I, France.
Harricane
M C
MC
Audemard
E
E
Mornet
D
D
D000199:Actins / Q000648:ultrastructure; D000595:Amino Acid Sequence; D000818:Animals; D001119:Arginase; D002918:Chymotrypsin / Q000378:metabolism; D005456:Fluorescent Dyes; D006801:Humans; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism; D015879:Myosin Subfragments / Q000302:isolation & purification* / Q000378:metabolism / Q000648:ultrastructure; D009218:Myosins / Q000302:isolation & purification / Q000378:metabolism; D009282:Naphthalenesulfonates; D011817:Rabbits; D012542:Scattering, Radiation; D012689:Sequence Homology, Nucleic Acid; D013917:Thrombin / Q000378:metabolism
D000199:Actins; D005456:Fluorescent Dyes; D015879:Myosin Subfragments; D009282:Naphthalenesulfonates; C006421:1,5-I-AEDANS; D002918:Chymotrypsin; D013917:Thrombin; D001119:Arginase; D009218:Myosins