Ester protein crosslinks
From Proteopedia
Ester bonds between threonine and glutamine sidechains can form covalent cross-links between polypeptide chains[1]. First observed in repetitive domains of a putative surface-anchored adhesin of Clostridium perfringens (Gram positive)[1], analysis of sequences suggested "that these intramolecular ester bonds are a widespread and common feature of cell surface adhesion proteins in Gram-positive bacteria"[1]. In the examples studied, the Thr-Gln ester bonds occur between the first and last beta strands of immunoglobulin-like domains, increasing thermal stability and resisance to proteases[1]. The structures containing such ester crosslinks "have in common is that they are very long and thin but also subject to large mechanical shear stresses and protease-rich environments"[1].
Examples
- 4ni6 REPEAT DOMAIN 1 OF CLOSTRIDIUM PERFRINGENS CPE0147
- 4mkm REPEAT DOMAINS 1 & 2 OF CLOSTRIDIUM PERFRINGENS CPE0147
Other Protein Crosslinks
In addition to the Ester crosslinks discussed above, other covalent cross-links between polypeptide chains include:
