Final answer:
The HSP-60 subunit contains an HUP domain with a core five ß-strand sheet in the 3-2-1-4-5 order and four α-helices, along with specific features that allow protein folding and ATP ligand binding.
Step-by-step explanation:
The domains in a subunit of HSP-60 (Heat Shock Protein 60) can be understood by examining the structural motif related to the HUP (HIGH-signature proteins, UspA, and PP-ATPase) domain class. According to structural comparisons, the HUP domain class, which includes HSP-60, features a core of five ß-strand sheets in the 3-2-1-4-5 order and four α-helices. These structural aspects allow HSP-60 to perform its function in protein folding and assembly. Specifically, the HUP domain includes the following features:
- A core of five ß-strand sheets in the 3-2-1-4-5 order.
- Four α-helices around the ß-sheet.
- A conserved sequence motif corresponding to ß-strand 4.
- A conserved small amino acid residue at the C-terminus of ß-strand 4.
- ATP ligand binding capability.
These features distinguish the HUP family, including HSP-60, from other domains with a Rossman-fold-like geometry and suggest a monophyletic origin of this domain class.