Structures of factor XI and prekallikrein bound to domain 6 of high–molecular weight kininogen reveal alternate domain 6 conformations and exosites

Li, Chan; Barroeta, Awital Bar; Wong, Szu Shen; Kim, Hyo Jung; Pathak, Monika; Dreveny, Ingrid; Meijers, Joost C.M.; Emsley, Jonas

Abstract

Background
High–molecular weight kininogen (HK) circulates in plasma as a complex with zymogen prekallikrein (PK). HK is both a substrate and a cofactor for activated plasma kallikrein, and the principal exosite interactions occur between PK N-terminal apple domains and the C-terminal D6 domain of HK.

Objectives
To determine the structure of the complex formed between PK apple domains and an HKD6 fragment and compare this with the coagulation factor XI (FXI)-HK complex.

Methods
We produced recombinant FXI and PK heavy chains (HCs) spanning all 4 apple domains. We cocrystallized PKHC (and subsequently FXIHC) with a 31-amino acid synthetic peptide spanning HK residues Ser565-Lys595 and determined the crystal structure. We also analyzed the full-length FXI-HK complex in solution using hydrogen deuterium exchange mass spectrometry.

Results
The 2.3Å PKHC-HK peptide crystal structure revealed that the HKD6 sequence WIPDIQ (Trp569-Gln574) binds to the apple 1 domain and HK FNPISDFPDT (Phe582-Thr591) binds to the apple 2 domain with a flexible intervening sequence resulting in a bent double conformation. A second 3.2Å FXIHC-HK peptide crystal structure revealed a similar interaction with the apple 2 domain but an alternate, straightened conformation of the HK peptide where residues LSFN (Leu579-Asn583) interacts with a unique pocket formed between the apple 2 and 3 domains. HDX-MS of full length FXI-HK complex in solution confirmed interactions with both apple 2 and apple 3.

Conclusions
The alternate conformations and exosite binding of the HKD6 peptide likely reflects the diverging relationship of HK to the functions of PK and FXI.

• Journal Article Type: Article
• Acceptance Date: Mar 24, 2023
• Publication Date: 2023-09
• Deposit Date: Dec 6, 2023
• Publicly Available Date: Dec 6, 2023
• Journal: Journal of Thrombosis and Haemostasis
• Print ISSN: 1538-7933
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 21
• Issue: 9
• Pages: 2378-2389
• DOI: https://doi.org/10.1016/j.jtha.2023.03.042
• Keywords: Hematology; factor IX; factor XI; factor XII; kininogens; prekallikrein
• Additional Information: This article is maintained by: Elsevier; Article Title: Structures of factor XI and prekallikrein bound to domain 6 of high–molecular weight kininogen reveal alternate domain 6 conformations and exosites; Journal Title: Journal of Thrombosis and Haemostasis; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.jtha.2023.03.042; Content Type: article; Copyright: Crown Copyright © 2023 Published by Elsevier Inc. on behalf of International Society on Thrombosis and Haemostasis.