Final answer:
The quaternary structure of HSP-90, a heat shock protein, involves two polypeptide subunits that form a dimer with a total weight of approximately 180 kDa. The stabilization of this structure relies on various interactions such as hydrogen bonding and ionic bonding.
Step-by-step explanation:
Quaternary Structure of HSP-90 Proteins
The quaternary structure of proteins refers to the assembly and arrangement of multiple polypeptide subunits in a protein complex. Specifically, HSP-90 (heat shock protein 90) typically functions as a dimer in its active form, meaning it consists of two polypeptide subunits. The weight of HSP-90 can vary, but generally, each subunit is approximately 90 kDa, leading to a total molecular weight of about 180 kDa for the dimer. The stabilization of the quaternary structure is influenced by multiple types of bonding interactions, including hydrogen bonding, ionic bonding, disulfide linkages, and dispersion forces. These weak interactions between the subunits are crucial for maintaining the functional conformation of the HSP-90 proteins.