IDENTIFICATION AND CHARACTERIZATION OF THE KLCMD1 GENE ENCODING KLUYVEROMYCES-LACTIS CALMODULIN

The KlCMD1 gene was isolated from a Kluyveromyces lactis genomic libra ry as a suppressor of the Saccharomyces cerevisiae temperature-sensiti ve mutant spc110-124, an allele previously shown to be suppressed by e levated copy number of the S. cerevisiae calmodulin gene CMD1. The KlC MD1 gene encodes a polypeptide which is 95% identical to S. cerevisiae calmodulin and 55% identical to calmodulin from Schizosaccharomyces p ombe. Complementation of a S, cerevisiae cmd1 deletion mutant by KICMD 1 demonstrates that this gene encodes a functional calmodulin homologu e. Multiple sequence alignment of calmodulins from yeast and multicell ular eukaryotes shows that the K. lactis and S. cerevisiae calmodulins are considerably more closely related to each other than to other cal modulins, most of which have four functional Ca2+-binding EF hand doma ins. Thus like its S. cerevisiae counterpart Cmd1p, the KlCMD1 product is predicted to form only three Ca2+-binding motifs. The KlCMD1 seque nce has been assigned Accession Number AJ002021 in the EMBL/GenBank da tabase. (C) 1998 John Wiley & Sons, Ltd.