Mapping of the region of the heavy chain of myosin subfragment 1 that can be crosslinked to the alkali light chains.

Earlier studies have shown that the presence of MgATP considerably diminishes the efficiency of crosslinking of the alkali light chains to the heavy chain of myosin subfragment 1 (S1) with dithiobis (succinimidylpropionate) (DSP). To localize the region of the nucleotide-induced change, a non-cleavable analog of DSP, disuccinimidyl suberate (DSS) was used. The products of crosslinking between the alkali light chains and the 27 kDa tryptic fragment of the heavy chain were isolated and further cleaved with N-chlorosuccinimide (NCS) or with formic acid. Mapping of the resulting peptides on SDS gels locates the crosslinking site(s) in the heavy chain region spanning residues 42-112.