7ARX

Crystal structure of the catalytic fragment of masp-1 in complex with SFMI1

Summary for 7ARX

• Entry DOI: 10.2210/pdb7arx/pdb
• Descriptor: Mannan-binding lectin serine protease 1, SFMI1 - Sunflower MASP1 inhibitor, DI(HYDROXYETHYL)ETHER, ... (5 entities in total)
• Functional Keywords: protease, inhibitor, complex, immune system
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 3
• Total formula weight: 47114.96

Authors

Durvanger, Z.,Harmat, V.,Dobo, J.,Megyeri, M. (deposition date: 2020-10-26, release date: 2021-11-03, Last modification date: 2024-11-13)

Primary citation

Durvanger, Z.,Boros, E.,Nagy, Z.A.,Hegedus, R.,Megyeri, M.,Dobo, J.,Gal, P.,Schlosser, G.,Angyan, A.F.,Gaspari, Z.,Perczel, A.,Harmat, V.,Mezo, G.,Menyhard, D.K.,Pal, G.
Directed Evolution-Driven Increase of Structural Plasticity Is a Prerequisite for Binding the Complement Lectin Pathway Blocking MASP-Inhibitor Peptides.
Acs Chem.Biol., 17:969-986, 2022

PubMed Abstract: MASP-1 and MASP-2 are key activator proteases of the complement lectin pathway. The first specific mannose-binding lectin-associated serine protease (MASP) inhibitors had been developed from the 14-amino-acid sunflower trypsin inhibitor (SFTI) peptide by phage display, yielding SFTI-based MASP inhibitors, SFMIs. Here, we present the crystal structure of the MASP-1/SFMI1 complex that we analyzed in comparison to other existing MASP-1/2 structures. Rigidified backbone structure has long been accepted as a structural prerequisite for peptide inhibitors of proteases. We found that a hydrophobic cluster organized around the P2 Thr residue is essential for the structural stability of wild-type SFTI. We also found that the same P2 Thr prevents binding of the rigid SFTI-like peptides to the substrate-binding cleft of both MASPs as the cleft is partially blocked by large gatekeeper enzyme loops. Directed evolution removed this obstacle by replacing the P2 Thr with a Ser, providing the SFMIs with high-degree structural plasticity, which proved to be essential for MASP inhibition. To gain more insight into the structural criteria for SFMI-based MASP-2 inhibition, we systematically modified MASP-2-specific SFMI2 by capping its two termini and by replacing its disulfide bridge with varying length thioether linkers. By doing so, we also aimed to generate a versatile scaffold that is resistant to reducing environment and has increased stability in exopeptidase-containing biological environments. We found that the reduction-resistant disulfide-substituted l-2,3-diaminopropionic acid (Dap) variant possessed near-native potency. As MASP-2 is involved in the life-threatening thrombosis in COVID-19 patients, our synthetic, selective MASP-2 inhibitors could be relevant coronavirus drug candidates.

PubMed: 35378038
DOI: 10.1021/acschembio.2c00114

Experimental method

X-RAY DIFFRACTION (2.42 Å)