4TVB

Crystal Structure of the Homospermidine Synthase (HSS) from Blastochloris viridis in Complex with NAD, Putrescine and sym-Homospermidine

Summary for 4TVB

• Entry DOI: 10.2210/pdb4tvb/pdb
• Related: 4PLP
• Descriptor: Homospermidine synthase, 1,4-DIHYDRONICOTINAMIDE ADENINE DINUCLEOTIDE, sym-homospermidine, ... (7 entities in total)
• Functional Keywords: homospermidine synthase, oxidoreductase, transferase, rossman fold
• Biological source: Blastochloris viridis
• Total number of polymer chains: 2
• Total formula weight: 107738.41

Authors

Krossa, S. (deposition date: 2014-06-26, release date: 2015-07-08, Last modification date: 2023-12-20)

Primary citation

Krossa, S.,Faust, A.,Ober, D.,Scheidig, A.J.
Comprehensive Structural Characterization of the Bacterial Homospermidine Synthase-an Essential Enzyme of the Polyamine Metabolism.
Sci Rep, 6:19501-19501, 2016

PubMed Abstract: The highly conserved bacterial homospermidine synthase (HSS) is a key enzyme of the polyamine metabolism of many proteobacteria including pathogenic strains such as Legionella pneumophila and Pseudomonas aeruginosa; The unique usage of NAD(H) as a prosthetic group is a common feature of bacterial HSS, eukaryotic HSS and deoxyhypusine synthase (DHS). The structure of the bacterial enzyme does not possess a lysine residue in the active center and thus does not form an enzyme-substrate Schiff base intermediate as observed for the DHS. In contrast to the DHS the active site is not formed by the interface of two subunits but resides within one subunit of the bacterial HSS. Crystal structures of Blastochloris viridis HSS (BvHSS) reveal two distinct substrate binding sites, one of which is highly specific for putrescine. BvHSS features a side pocket in the direct vicinity of the active site formed by conserved amino acids and a potential substrate discrimination, guiding, and sensing mechanism. The proposed reaction steps for the catalysis of BvHSS emphasize cation-π interaction through a conserved Trp residue as a key stabilizer of high energetic transition states.

PubMed: 26776105
DOI: 10.1038/srep19501

Experimental method

X-RAY DIFFRACTION (1.689 Å)