ACTIVE-SITE COMPARISONS HIGHLIGHT STRUCTURAL SIMILARITIES BETWEEN MYOSIN AND OTHER P-LOOP PROTEINS

The phosphate binding loop (P-loop) is a common feature of a large num ber of enzymes that bind nucleotide whose consensus sequence is often used as a fingerprint for identifying new members of this group. We re view here the binding sites of nine purine nucleotide binding proteins , with a focus on their relationship to the active site of myosin. Thi s demonstrates that there is considerable conservation in the distribu tion and nature of the ligands that coordinate the triphosphate moiety . This comparison further suggests that at least myosin and the G-prot eins utilize a similar mechanism for nucleotide hydrolysis.