PDBsum entry 1h7k

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Oxidoreductase PDB id
Protein chain
476 a.a. *
Waters ×168
* Residue conservation analysis

References listed in PDB file
Key reference
Title Formation of a tyrosyl radical intermediate in proteus mirabilis catalase by directed mutagenesis and consequences for nucleotide reactivity.
Authors P.Andreoletti, S.Gambarelli, G.Sainz, V.Stojanoff, C.White, G.Desfonds, J.Gagnon, J.Gaillard, H.M.Jouve.
Ref. Biochemistry, 2001, 40, 13734-13743. [DOI no: 10.1021/bi010687f]
PubMed id 11695923
Proteus mirabilis catalase (PMC) belongs to the family of NADPH binding catalases. The function of NADPH in these enzymes is still a matter of debate. This study presents the effects of two independent phenylalanine mutations (F194 and F215), located between NADPH and heme in the PMC structure. The phenylalanines were replaced with tyrosines which we predicted could carry radicals in a NADPH-heme electron transfer. The X-ray crystal structures of the two mutants indicated that neither the binding site of NADPH nor the immediate environment of the residues was affected by the mutations. Measurements using H2O2 as a substrate confirmed that the variants were as active as the native enzyme. With equivalent amounts of peroxoacetic acid, wild-type PMC, F215Y PMC, and beef liver catalase (BLC) formed a stable compound I, while the F194Y PMC variant produced a compound I which was rapidly transformed into compound II and a tyrosyl radical. EPR studies showed that this radical, generated by the oxidation of Y194, was not related to the previously observed radical in BLC, located on Y369. In the presence of excess NADPH, compound I was reduced to a resting enzyme (k(obs) = 1.7 min(-1)) in a two-electron process. This was independent of the enzyme's origin and did not require any thus far identified tyrosyl radicals. Conversely, the presence of a tyrosyl radical in F194Y PMC greatly enhanced the oxidation of reduced beta-nicotinamide mononucleotide under a steady-state H2O2 flow with observable compound II. This process could involve a one-electron reduction of compound I via Y194.
Secondary reference #1
Title Ferryl intermediates of catalase captured by time-Resolved weissenberg crystallography and uv-Vis spectroscopy.
Authors P.Gouet, H.M.Jouve, P.A.Williams, I.Andersson, P.Andreoletti, L.Nussaume, J.Hajdu.
Ref. Nat Struct Biol, 1996, 3, 951-956.
PubMed id 8901874
Secondary reference #2
Title Crystal structure of proteus mirabilis pr catalase with and without bound NADPH.
Authors P.Gouet, H.M.Jouve, O.Dideberg.
Ref. J Mol Biol, 1995, 249, 933-954.
PubMed id 7791219
Secondary reference #3
Title Crystallization and crystal packing of proteus mirabilis pr catalase.
Authors H.M.Jouve, P.Gouet, N.Boudjada, G.Buisson, R.Kahn, E.Duee.
Ref. J Mol Biol, 1991, 221, 1075-1077.
PubMed id 1942042
Secondary reference #4
Title The refined structure of beef liver catalase at 2.5 angstroms resolution
Authors I.Fita, A.M.Silva, M.R.N.Murthy, M.G.Rossmann.
Ref. acta crystallogr ,sect b, 1986, 42, 497.
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