Conservation within the myosin motor domain: implications for structure and function.
BACKGROUND
Myosins are motors that use energy supplied by ATP to travel along actin filaments. The structure of myosin is known, but the actin-binding site is not well defined, and the mechanisms by which actin activates ATP hydrolysis by myosin, and myosin moves relative to the actin filament, developing force, are not fully understood. Previous phylogenetic analyses of the motor domain of myosins have identified up to twelve classes. We set out to analyse the positions of conserved residues within this domain in detail, and relate the conserved residues to the myosin structure.


RESULTS
Our analysis indicates that there are at least thirteen myosin classes. Conserved residues in the motor domain have been positioned within the framework provided by the recent crystal structures, thus helping to define those residues involved in actin and ATP binding, in hydrolysis and in conformational change. This has revealed remarkably poor overall conservation at the site thought to be involved in actin binding, but several highly conserved residues have been identified that may be functionally important.


CONCLUSIONS
Information from such a sequence analysis is a useful tool in the further interpretation of X-ray structures. It allows the position of crucial residues from other members of a superfamily to be determined within the framework provided by the known structures and the functional significance of conserved or mutated residues to be assessed.
Cope
M J
MJ
MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 2QH, England.
Whisstock
J
J
Rayment
I
I
Kendrick-Jones
J
J
D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000828:Animal Population Groups / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000917:Antibody Formation; D002645:Chickens / Q000378:metabolism; D016384:Consensus Sequence; D018360:Crystallography, X-Ray; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D019143:Evolution, Molecular; D006868:Hydrolysis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009218:Myosins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D010944:Plants / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013329:Structure-Activity Relationship
D000199:Actins; D000939:Epitopes; D010940:Plant Proteins; D000255:Adenosine Triphosphate; D009218:Myosins