[Thin filaments of molluscan catch muscles contain a calponin-like protein].

A novel 40 kDa protein was detected in native thin filaments from catch muscles of the mussel Crenomytilus grayanus. The MALDY-TOF analysis of the protein showed a 40% homology with the calponin-like protein from the muscle of Mytilus galloprovincialis (45 kDa), which has a 36% homology with smooth muscle calponin from chicken gizzard (34 kDa). The amount of the calponin-like protein in thin filaments depends on isolation conditions and varies from the complete absence to the presence in amounts comparable with that of tropomyosin.

[Expression of several domains of twitchin and myorod in the ontogenesis of mussel Mytilus trossulus].

The expression of MLCK- and PEVK-domains of twitchin, as well as the unique N-terminal domain of myorod in early development of the mussel Mytilus trossulus has been studied. The MLCK-domain of twitchin and the unique N-terminal domain of myorod appear at the early stages of development, whereas the PEVK-domain of twitchin is present only in muscles of adult mussel. The sizes of genes of the N-terminal domain of myorod, obtained at the blastula stage and from the adult animal are similar, but the proteins have significant differences in the amino acid sequences.

[Polymerization of myorod, a surface protein of thick filaments of molluscan smooth muscle].

The study is concerned with the polymerization of myorod, a protein from thick filaments of molluscan smooth muscles, which is an alternative product of the gene of myosin heavy chains. The dependences of the properties and polymer structure of myorod on the conditions of its formation were investigated. It was shown that myorod loses the ability to form viscous polymers after proteolytic removal of the unique sequence.

[N-ethylmaleimide inhibits polymerization of myorod, a contractile protein of thick filaments of molluscan smooth muscles].

The effect of N-ethylmaleimide on the polymerization of myorod, a protein of molluscan smooth muscles, which is colocalized with myosin on the surface of paramyosin core of thick filaments and is a product of the alternative splicing of the gene of heavy myosin chains, was studied. It was shown that myorod modified by N-ethylmaleimide completely loses the polymerization ability but acquires the ability to aggregate in the presence of Mg2+. At the same time, treatment of molluscan myosin with N-ethylmaleimide did not affect its polymerization.