Download MendeleyBinding Differences of the Peptide-Substrate-Binding Domain of Collagen Prolyl 4-Hydroxylases I and II for Proline- and Hydroxyproline-Rich Peptides.
Rahman, M.M., Sulu, R., Adediran, B., Tu, H., Salo, A.M., Murthy, S., Myllyharju, J., Wierenga, R.K., Koski, M.K.(2025) Proteins 93: 1732-1746
- PubMed: 40386874
- DOI: https://doi.org/10.1002/prot.26839
- Primary Citation of Related Structures:
9HPQ, 9HRE, 9HT8, 9HTD - PubMed Abstract:
Collagen prolyl 4-hydroxylase (C-P4H) catalyzes the 4-hydroxylation of Y-prolines of the XYG-repeat of procollagen. C-P4Hs are tetrameric α 2 β 2 enzymes. The α-subunit provides the N-terminal dimerization domain, the middle peptide-substrate-binding (PSB) domain, and the C-terminal catalytic (CAT) domain. There are three isoforms of the α-subunit, complexed with a β-subunit that is protein disulfide isomerase, forming C-P4H I-III. The PSB domain of the α-subunit binds proline-rich peptides, but its function with respect to the prolyl hydroxylation mechanism is unknown. An extended mode of binding of proline-rich peptides (PPII, polyproline type-II, conformation) to the PSB-I domain has previously been reported for the PPG-PPG-PPG and P9 peptides. Crystal structures now show that peptides with the motif PxGP (PPG-PRG-PPG, PPG-PAG-PPG) (where x, at Y-position 5, is not a proline) bind to the PSB-I domain differently, more deeply, in the peptide-binding groove. The latter mode of binding has previously been reported for structures of the PSB-II domain complexed with these PxGP-peptides. In addition, it is shown here by crystallographic binding studies that the POG-PAG-POG peptide (with 4-hydroxyprolines at Y-positions 2 and 8) also adopts the PxGP mode of binding to PSB-I as well as to PSB-II. Calorimetric binding studies show that the affinities of these peptides are lower for PSB-I than for PSB-II, with, respectively, K D values of about 70 μM for PSB-I and 20 μM for PSB-II. The importance of these results for understanding the reaction mechanism of C-P4H, in particular concerning the function of the PSB domain, is discussed.
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
Organizational Affiliation:
