CLONING AND SEQUENCING OF A GENE ENCODING A NEW MEMBER OF THE TETRATRICOPEPTIDE PROTEIN FAMILY FROM MAGNETOSOMES OF MAGNETOSPIRILLUM-MAGNETOTACTICUM

A gene encoding the 22-kDa protein (MAM22) which was localized in the magnetosomes isolated from the magnetotactic bacterium, Magnetospirill um magnetotacticum, was cloned and sequenced. MAM22 was composed of 22 0 amino acids (aa) with a molecular weight of 24 186 Da. The deduced a a sequence exhibited significant homology with a number of proteins th at belong to the tetratricopeptide repeat (TPR) protein family, includ ing mitochondrial protein import receptors and peroxisomal protein imp ort receptors. The presence of three repeats of a degenerate 34-aa con sensus sequence, suggest that MAM22 localized in magnetosome membranes may interact with the cytoplasmic proteins containing similar TPR mot ifs.