2YYL: Crystal Structure Of The Mutant Of Hpab (t198i, A276g, And R466h) Complexed With Fad

Citation:
Abstract
The 4-hydroxyphenylacetate (4HPA) 3-monooxygenase is involved in the initial step of the 4HPA degradation pathway and catalyzes 4HPA hydroxylation to 3,4-dihydroxyphenylacetate. This enzyme consists of two components, an oxygenase (HpaB) and a reductase (HpaC). To understand the structural basis of the catalytic mechanism of HpaB, crystal structures of HpaB from Thermus thermophilus HB8 were determined in three states: a ligand-free form, a binary complex with FAD, and a ternary complex with FAD and 4HPA. Structural analysis revealed that the binding and dissociation of flavin are accompanied by conformational changes of the loop between beta5 and beta6 and of the loop between beta8 and beta9, leading to preformation of part of the substrate-binding site (Ser-197 and Thr-198). The latter loop further changes its conformation upon binding of 4HPA and obstructs the active site from the bulk solvent. Arg-100 is located adjacent to the putative oxygen-binding site and may be involved in the formation and stabilization of the C4a-hydroperoxyflavin intermediate.
PDB ID: 2YYLDownload
MMDB ID: 59945
PDB Deposition Date: 2007/4/30
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 1.75  Å
Source Organism:
Similar Structures:
Biological Unit for 2YYL: tetrameric; determined by author and by software (PISA,PQS)
Molecular Components in 2YYL
Label Count Molecule
Proteins (4 molecules)
4
4-hydroxyphenylacetate-3-hydroxylase(Gene symbol: TTHA0960)
Molecule annotation
Chemicals (16 molecules)
1
12
2
4
* Click molecule labels to explore molecular sequence information.

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