1TBH

H141D mutant of rat liver arginase I

Summary for 1TBH

• Entry DOI: 10.2210/pdb1tbh/pdb
• Related: 1RLA 1TA1 1TBJ 1TBL
• Descriptor: Arginase 1, MANGANESE (II) ION (3 entities in total)
• Functional Keywords: arginase, h141d, binuclear manganese cluster, hydrolase
• Biological source: Rattus norvegicus (Norway rat)
• Cellular location: Cytoplasm: P07824
• Total number of polymer chains: 3
• Total formula weight: 102365.04

Authors

Cama, E.,Cox, J.D.,Ash, D.E.,Christianson, D.W. (deposition date: 2004-05-20, release date: 2005-08-16, Last modification date: 2024-02-14)

Primary citation

Colleluori, D.M.,Reczkowski, R.S.,Emig, F.A.,Cama, E.,Cox, J.D.,Scolnick, L.R.,Compher, K.,Jude, K.,Han, S.,Viola, R.E.,Christianson, D.W.,Ash, D.E.
Probing the role of the hyper-reactive histidine residue of arginase.
Arch.Biochem.Biophys., 444:15-26, 2005

PubMed Abstract: Rat liver arginase (arginase I) is potently inactivated by diethyl pyrocarbonate, with a second-order rate constant of 113M(-1)s(-1) for the inactivation process at pH 7.0, 25 degrees C. Partial protection from inactivation is provided by the product of the reaction, l-ornithine, while nearly complete protection is afforded by the inhibitor pair, l-ornithine and borate. The role of H141 has been probed by mutagenesis, chemical modulation, and X-ray diffraction. The hyper-reactivity of H141 towards diethyl pyrocarbonate can be explained by its proximity to E277. A proton shuttling role for H141 is supported by its conformational mobility observed among the known arginase structures. H141 is proposed to serve as an acid/base catalyst, deprotonating the metal-bridging water molecule to generate the metal-bridging hydroxide nucleophile, and by protonating the amino group of the product to facilitate its departure.

PubMed: 16266687
DOI: 10.1016/j.abb.2005.09.009

Experimental method

X-RAY DIFFRACTION (2.7 Å)