Zy. Wang et al., AMINO-ACID-SEQUENCE OF THE LIGHT-CHAIN OF ACANTHAMOEBA MYOSIN IC, Journal of muscle research and cell motility, 18(3), 1997, pp. 395-398
The amino acid sequence of the light chain of Acanthamoeba myosin IC d
educed from the cDNA sequence comprises 149 amino acids with a calcula
ted molecular weight of 16739. All but the 3 N-terminal residues were
also determined by amino acid sequencing of the purified protein, whic
h also showed the N-terminus to be blocked. Phylogenetic analysis show
s Acanthamoeba myosin IC light chain to be more similar to the calmodu
lin subfamily of EF-hand calcium-modulated proteins than to the myosin
II: essential light chain or regulatory Light chain subfamilies. In p
airwise comparisons, the myosin IC light chain sequence is most simila
r to sequences of calmodulins (similar to 50% identical) and a squid c
alcium-binding protein (similar to 43% identical); the sequence is sim
ilar to 37% identical to the calcium-binding essential light chain of
Physarum myosin II and similar to 30% identical to the essential light
chain of Acanthamoeba myosin II, and the essential light chain and re
gulatory light chain of Dictyostelium myosin II. The sequence predicts
four helix-loop-helix domains with possible calcium-binding sites in
domains I and III, suggesting that calcium may affect the activity of
this unconventional myosin. This is the first report of the sequence o
f an unconventional myosin light chain other than calmodulin.