FIG. 2.

Mitochondrial localization of TbDSS-1. (A) A putative mitochondrial targeting sequence is present in TbDSS-1. The putative N-terminal mitochondrial import sequence of TbDSS-1 was predicted by Target P v1.0. This sequence is aligned with the known and predicted targeting sequences from the T. brucei mitochondrial proteins TBmtRNAP, TBMP48, ISP, ATPase, RBP16, and gBP21 (8, 23, 26, 28, 35, 47). The characteristic one or two N-terminal arginine residues are shown as white letters on a black background. Serine and threonine residues (white letters on a gray background) flank hydrophobic residues that are shown in light gray. (B) Production of bacterially expressed His₆-TbDSS-1 (6XHis-TbDSS-1). Proteins were electrophoresed on SDS-PAGE and stained with Coomassie blue. M, molecular mass markers; Un, extracts from uninduced cells; In, extracts from induced cells; P, nickel column-purified His₆-TbDSS-1. (C) TbDSS-1 is enriched in mitochondria. Anti-TbDSS-1 antibodies were used to probe blots containing 10 or 25 μg of procyclic-form T. brucei whole-cell or mitochondrial extracts. Anti-RBP16 antibodies (26) were used as a positive control for a known mitochondrial protein.