4PA5

Tgl - a bacterial spore coat transglutaminase - cystamine complex

Summary for 4PA5

• Entry DOI: 10.2210/pdb4pa5/pdb
• Related: 4P8I
• Descriptor: Protein-glutamine gamma-glutamyltransferase, TRIETHYLENE GLYCOL, 1,2-ETHANEDIOL, ... (10 entities in total)
• Functional Keywords: protein cross-linking, baterial spore coat, nlpc/p60 endopeptidase, papain, transferase
• Biological source: Bacillus subtilis
• Total number of polymer chains: 2
• Total formula weight: 61313.72

Authors

Brito, J.A.,Placido, D.,Fernandes, C.G.,Lousa, D.,Isidro, A.,Soares, C.M.,Pohl, J.,Carrondo, M.A.,Henriques, A.O.,Archer, M. (deposition date: 2014-04-07, release date: 2015-09-30, Last modification date: 2024-05-01)

Primary citation

Fernandes, C.G.,Placido, D.,Lousa, D.,Brito, J.A.,Isidro, A.,Soares, C.M.,Pohl, J.,Carrondo, M.A.,Archer, M.,Henriques, A.O.
Structural and Functional Characterization of an Ancient Bacterial Transglutaminase Sheds Light on the Minimal Requirements for Protein Cross-Linking.
Biochemistry, 54:5723-5734, 2015

PubMed Abstract: Transglutaminases are best known for their ability to catalyze protein cross-linking reactions that impart chemical and physical resilience to cellular structures. Here, we report the crystal structure and characterization of Tgl, a transglutaminase from the bacterium Bacillus subtilis. Tgl is produced during sporulation and cross-links the surface of the highly resilient spore. Tgl-like proteins are found only in spore-forming bacteria of the Bacillus and Clostridia classes, indicating an ancient origin. Tgl is a single-domain protein, produced in active form, and the smallest transglutaminase characterized to date. We show that Tgl is structurally similar to bacterial cell wall endopeptidases and has an NlpC/P60 catalytic core, thought to represent the ancestral unit of the cysteine protease fold. We show that Tgl functions through a unique partially redundant catalytic dyad formed by Cys116 and Glu187 or Glu115. Strikingly, the catalytic Cys is insulated within a hydrophobic tunnel that traverses the molecule from side to side. The lack of similarity of Tgl to other transglutaminases together with its small size suggests that an NlpC/P60 catalytic core and insulation of the active site during catalysis may be essential requirements for protein cross-linking.

PubMed: 26322858
DOI: 10.1021/acs.biochem.5b00661

Experimental method

X-RAY DIFFRACTION (1.86 Å)