Hsm3 is a proteasome-dedicated chaperone that forms a base precursor, Hsm3-Rpt1-Rpt2-Rpn1 [1]. Hsm3 consists of 23 alpha-helices forming 11 repeats similar to the HEAT repeats. This entry includes the first 5 repeats at the N-terminal.

1: Structural basis for specific recognition of Rpt1p, an ATPase subunit of 26 S proteasome, by proteasome-dedicated chaperone Hsm3p. Takagi K, Kim S, Yukii H, Ueno M, Morishita R, Endo Y, Kato K, Tanaka K, Saeki Y, Mizushima T; J Biol Chem. 2012;287:12172-12182. PMID:22334676