Amino acid sequence of a segment of the Acanthamoeba myosin II heavy chain containing all three regulatory phosphorylation sites.

摘要: The actin-activated Mg2+-ATPase activity of myosin II from the soil amoeba Acanthamoeba castellanii is regulated by phosphorylation 3 serine residues on heavy chain. Partial chymotryptic digestion 32P-labeled cleaves tail end chain a small peptide which contains all three sites. During purification phosphorylated resolved into several different species as result heterogeneity both in phosphate content and size (probably due to cleavage at carboxyl terminus). However, forms have an identical amino terminus. sequence first 58 is: N-S-A-L-E-S-D-K-Q-I10-L-E-D-E-I-G-D-L-H- E20-K-N-K-Q-L-Q-A-K-I-A30-Q-L-Q-D-E-I-D-G-T- P40-S-S-R-G-G-S-T-R-G-A50-S-A-R-G-A-S-V-R. serines are positions 46, 51, 56. 36 display repeating 3-4-3-4 pattern hydrophobic suggesting that this section alpha-helical coiled-coil structure. A -Gly-Thr-Pro 38-40 disrupts alpha-helix and, same point, non-polar lost. It likely extending Gly-38 tail, include phosphorylatable serines, form randomly coiled or globular This report around regulatory sites any