9CR5

Crystal structure of GNAT superfamily acetyltransferase PA2271 from Pseudomonas aeruginosa

Summary for 9CR5

• Entry DOI: 10.2210/pdb9cr5/pdb
• Descriptor: Acetyltransferase PA2271, ACETYL COENZYME *A, SODIUM ION, ... (5 entities in total)
• Functional Keywords: gnat, acetyltransferase, structural genomics, psi-2, protein structure initiative, midwest center for structural genomics, mcsg, transferase
• Biological source: Pseudomonas aeruginosa
• Total number of polymer chains: 2
• Total formula weight: 40938.54

Authors

Majorek, K.A.,Cooper, D.R.,Joachimiak, A.,Minor, W.,Midwest Center for Structural Genomics (MCSG) (deposition date: 2024-07-20, release date: 2025-05-28)

Primary citation

Uychoco, P.,Majorek, K.A.,Ives, A.N.,Le, V.T.B.,Caro De Silva, P.L.,Paurus, V.L.,Attah, I.K.,Lipton, M.S.,Minor, W.,Kuhn, M.L.
Structural, functional, and regulatory evaluation of a cysteine post-translationally modified Gcn5-related N-acetyltransferase.
Biochem.Biophys.Res.Commun., 748:151299-151299, 2025

PubMed Abstract: Polyamines within the cell are tightly regulated by spermidine/spermine N-acetyltransferase (SSAT) enzymes. While several SSATs have been investigated in different bacterial species, there is still a significant gap in knowledge about which proteins are functional SSATs in many organisms. For example, while it is known that Pseudomonas aeruginosa synthesizes the polyamine spermidine, the SSAT that acetylates this molecule and its importance in regulating intracellular polyamines remains unknown. We previously identified a candidate Gcn5-related N-acetyltransferase (GNAT) protein from P. aeruginosa (PA2271) that could fulfill this role since it acetylates spermidine, but no further studies were conducted. Here, we explored the structure/function relationship of the PA2271 protein by determining its X-ray crystal structure and performing enzyme kinetics assays. We also identified active site residues that are essential for catalysis and substrate binding. As the study progressed, we encountered results that led us to explore the importance of four cysteine residues on enzyme activity and disulfide bond formation or modification of cysteine residues. We found these cysteine residues in PA2271 are important for protein solubility and activity, and there is an interrelationship between cysteine residues that contribute to these effects. Furthermore, we also found disulfide bonds could form between C and C and speculate that these residues may contribute to redox regulation of PA2271 protein activity.

PubMed: 39826527
DOI: 10.1016/j.bbrc.2025.151299

Experimental method

X-RAY DIFFRACTION (1.56 Å)