Myosin-Va is a molecular motor with an elongated neck domain composed of six tandem IQ-motifs that bind calmodulins. Calcium regulates the mechanochemical activities of myosin Va, in a stringent and highly cooperative manner, via binding to the calmodulins bound to the neck domain. Interactions between calmodulin and synthetic peptides via intrinsic fluorescence of tryptophan have been determined in the presence and absence of calcium. The structural determination of the IQ-calmodulin complexes of myosin V, however, has proved illusive. We have cloned and expressed in bacteria recombinant proteins corresponding to tandem IQs 1+2 and 5+6 based on myosin Va amino acid sequence in order to investigate the biochemical and structural aspects of their binding to calmodulin. Complementing this study and as a way to formulate hypotheses, we have generated a 3-D molecular model from sequence data of the complete neck domain of myosin Va using the freeware program ArgusLab. Its overall structure is a long, uninterrupted, basic, amphipathic alpha - helix with a slight curvature from amino - to carboxy - terminal. Docking of the crystal structure of calmodulin onto this model, using the freeware program Hex, has produced a plausible structure for the calmodulin-IQ1 complex. This has been tested by correlating the specific orientation of alpha - helices in the model with homologous alpha - helices in the known crystal structures of calmodulin-related proteins bound to IQ sequences. Attempts at docking calmodulin to IQs 2 – 6 have shown more diversity in structural orientation and may reflect the diversity in binding properties of calmodulin to the different IQ sites.