MAM33P, AN OLIGOMERIC, ACIDIC PROTEIN IN THE MITOCHONDRIAL MATRIX OF SACCHAROMYCES-CEREVISIAE IS RELATED TO THE HUMAN-COMPLEMENT RECEPTOR GCLQ-R

Mam33p (mitochondrial acidic matrix protein) is a soluble protein, loc ated in mitochondria of Saccharomyces cerevisiae. It is synthesized as a precursor with an N-terminal mitochondrial targeting sequence that is processed on import. Mam33p assembles to a homo-oligomeric complex in the mitochondrial matrix. It can bind to the sorting signal of cyto chrome b(2) that directs this protein into the intermembrane space. Ma m33p is encoded by an 801 bp open reading frame. Gene disruption did n ot result in a significant growth defect. Mam33p exhibits sequence sim ilarity to gC1q-R, a human protein that has been implicated in the bin ding of complement factor C1q and kininogen. (C) 1998 John Wiley & Son s, Ltd.