HscB Iron Sulfur Cluster Co Chaperone Homolog (HSCB)

The deduced 235-amino acid protein contains an N-terminal mitochondrial targeting signal, followed by a putative J domain, a short loop, and a C-terminal domain folded into a compact 3-helix bundle. The J domain includes a J-domain signature motif (his-pro-asp). Like the E. coli homolog, the N and C termini of HSC20 interact through an extensive hydrophobic interface.  HSC20 shares 34% and 29% amino acid identity with E. coli Hsc20 and yeast JAC1, respectively. Northern blot analysis detected highest expression in liver, muscle, and heart, with low expression in all other tissues examined. A transcript of about 2.5 kb was detected in adult and fetal liver, and transcripts of about 1.4 and 6.0 kb were detected in heart and skeletal muscle.