Six putative IQ motifs of the recombinant chicken intestinal brush border myosin I are involved in calmodulin binding.
Chicken brush border myosin I has up to six IQ sequence motifs at which it may bind calmodulin. To determine the relative contributions of these motifs to calmodulin binding, fusion deletion fragments were expressed in Escherichia coli and their ability to bind calmodulin was assessed by the gel overlay technique. The first three N-terminal IQ sites showed strong binding with calmodulin. Surprisingly, the last three incomplete IQ motifs also contributed substantial calmodulin binding. The first and fourth IQ sites bound calmodulin but tended to reduce binding in combination with other sites. The data indicate that interactions among all six IQ motifs contribute to the ability of myosin I to bind calmodulin.
Khoroshev
M I
MI
Department of Medicine, University of California, Veterans Affairs Medical Center, San Francisco, California, 94121, USA. mkhoroshev@hotmail.com
Munson
S J
SJ
Bikle
D D
DD
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D002645:Chickens; D007457:Iodine Radioisotopes / Q000378:metabolism; D008871:Microvilli / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary; D011869:Radioligand Assay; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000378:metabolism*
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins