p23_like domain found in human (h) butyrate-induced transcript 1 (B-ind1) and similar proteins. hB-ind1 participates in signaling by the small GTPase Rac1. It binds to Rac1 and enhances different Rac1 effects including activation of nuclear factor (NF) kappaB and activation of c-Jun N-terminal kinase (JNK). hB-ind1 also plays a part in the RNA replication and particle production of Hepatitis C virus (HCV) through its interaction with heat shock protein Hsp90, HCV nonstructural protein 5A (NS5A), and the immunophilin FKBP8. hB-ind1 is upregulated in the outer layer of Chinese hamster V79 cells grown as multicell spheroids, versus in the same cells grown as monolayers. This group includes the Saccharomyces cerevisiae Sba1, a co-chaperone of the Hsp90. Sba1 has been shown to be is required for telomere length maintenance, and may modulate telomerase DNA-binding activity.
Structure:2CG9; Saccharomyces cerevisiae, showing two symmetrically disposed Sba1molecules complexed with a yeast Hsp90 (Hsp82) homodimer, contacts at 3.5A.
Comment:in this Hsp90-nucleotide-p23 (Sba1) closed chaperone complex each Sba1 molecule contacts both monomers of the Hsp90 (Hsp82) dimer.
Comment:this is a lower resolution structure (Resolution 3.10 A, R-Value of 0.314, R-Free of 0.353, and the overall B factors average 70 or above). A caution that the co-ordinates of the first block may not be correctly assigned as this sequence-conserved region is assigned a different position structurally in the other alpha-crystallin-type Hsps and p23-like structures.
Jiyao W et al.(2023). "The conserved domain database in 2023.",