1PSC

PHOSPHOTRIESTERASE FROM PSEUDOMONAS DIMINUTA

Summary for 1PSC

• Entry DOI: 10.2210/pdb1psc/pdb
• Descriptor: PHOSPHOTRIESTERASE, CADMIUM ION, DIETHYL 4-METHYLBENZYLPHOSPHONATE, ... (5 entities in total)
• Functional Keywords: hydrolase, phosphoric triester
• Biological source: Brevundimonas diminuta
• Cellular location: Cell membrane; Peripheral membrane protein: P0A434
• Total number of polymer chains: 2
• Total formula weight: 79121.45

Authors

Benning, M.M.,Holden, H.M. (deposition date: 1995-04-25, release date: 1997-04-01, Last modification date: 2024-06-05)

Primary citation

Benning, M.M.,Kuo, J.M.,Raushel, F.M.,Holden, H.M.
Three-dimensional structure of the binuclear metal center of phosphotriesterase.
Biochemistry, 34:7973-7978, 1995

PubMed Abstract: Phosphotriesterase, as isolated from Pseudomonas diminuta, is capable of detoxifying widely used pesticides such as paraoxon and parathion and various mammalian acetylcholinesterase inhibitors. The enzyme requires a binuclear metal center for activity. Recently, the three-dimensional structure of the apoenzyme was solved (Benning et al., 1994) and shown to consist of an alpha/beta-barrel. Here we describe the three-dimensional structure of the holoenzyme, reconstituted with cadmium, as determined by X-ray crystallographic analysis to 2.0-A resolution. Crystals employed in the investigation belonged to the space group C2 with unit cell dimensions of a = 129.5 A, b = 91.4 A, c = 69.4 A, beta = 91.9 degrees, and two subunits in the asymmetric unit. There are significant differences in the three-dimensional architecture of the apo and holo forms of the enzyme such that their alpha-carbon positions superimpose with a root-mean-square deviation of 3.4 A. The binuclear metal center is located at the C-terminus of the beta-barrel with the cadmiums separated by 3.8 A. There are two bridging ligands to the metals: a water molecule (or possibly a hydroxide ion) and a carbamylated lysine residue (Lys 169). The more buried cadmium is surrounded by His 55, His 57, Lys 169, Asp 301, and the bridging water in a trigonal bipyramidal arrangement. The second metal is coordinated in a distorted octahedral geometry by His 201, His 230, Lys 169, the bridging water molecule, and two additional solvents.

PubMed: 7794910
DOI: 10.1021/bi00025a002

Experimental method

X-RAY DIFFRACTION (2 Å)