Journal Article

PUBDB-2025-02317

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Binding 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. (Corresponding author) ; Koski, M. K. (Corresponding author)

2025
Wiley-Liss New York, NY

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Please use a persistent id in citations: doi:10.1002/prot.26839  doi:10.3204/PUBDB-2025-02317

Abstract: Collagen prolyl 4-hydroxylase (C-P4H) catalyzes the 4-hydroxylation of Y-prolines of the XYG-repeat of procollagen. C-P4Hs are tetrameric α2β2 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, KD 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.

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Contributing Institute(s):

1. EMBL-User (EMBL-User)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)

Experiment(s):

1. PETRA Beamline P14 (PETRA III)

Appears in the scientific report 2025

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Database coverage:
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