8WKD image
Entry Detail
PDB ID:
8WKD
Keywords:
Title:
Connectase T1A C192S mutant from Methanocaldococcus mazei with peptide substrate
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2023-09-27
Release Date:
2025-01-15
Method Details:
Experimental Method:
Resolution:
1.98 Å
R-Value Free:
0.26
R-Value Work:
0.21
R-Value Observed:
0.22
Space Group:
P 21 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:DUF2121 domain-containing protein
Mutations:C192S
Chain IDs:A
Chain Length:192
Number of Molecules:1
Biological Source:Methanosarcina mazei
Polymer Type:polypeptide(L)
Description:Tetrahydromethanopterin S-methyltransferase subunit A
Mutations:F11V,D14K
Chain IDs:B (auth: C)
Chain Length:20
Number of Molecules:1
Biological Source:Methanosarcina mazei
Primary Citation
Structural Basis of High-Precision Protein Ligation and Its Application.
J.Am.Chem.Soc. 147 1604 1611 (2025)
PMID: 39745918 DOI: 10.1021/jacs.4c10689

Abstact

Enzyme-catalyzed protein modifications have become invaluable in diverse applications, outperforming chemical methods in terms of precision, conjugation efficiency, and biological compatibility. Despite significant advances in ligases, such as sortase A and OaAEP1, their use in heterogeneous biological environments remains constrained by limited target sequence specificity. In 2021, Lupas' group introduced Connectase, a family of repurposed archaeal proteases for protein ligations, but its low processivity and lack of structural information have impeded further engineering for practical biological and biophysical applications. Here, we present the X-ray crystallographic structures of MmConnectase (Methanococcus maripaludis, MmCET) in both apo and substrate-bound forms. Comparative analysis with its inactive paralogue, MjCET (Methanococcus janaschi), reveals the structural basis of MmCET's high-precision ligation activity. We propose modifications to the N-terminal substrate recognition motifs to suppress MmCET's reversible protease activity, enabling high-precision protein ligations in complex biological environments, such as serum-containing cell cultures. To further demonstrate the enhanced processivity and precision, single-molecule protein unfolding experiments showed that our optimized Connectase, in conjunction with OaAEP1(C247A), can perform stepwise tandem ligations of protein leading to a well-defined protein polymer.

Legend

Protein

Chemical

Disease

Primary Citation of related structures