5SYV: Crystal Structure Of Burkholderia Pseudomallei Katg N240d Variant

Citation:
Abstract
The unusual Met-Tyr-Trp adduct composed of cross-linked side chains along with an associated mobile Arg is essential for catalase activity in catalase-peroxidases. In addition, acidic residues in the entrance channel, in particular an Asp and a Glu approximately 7 and approximately 15 A, respectively, from the heme, significantly enhance catalase activity. The mechanism by which these channel carboxylates influence catalase activity is the focus of this work. Seventeen new variants with fewer and additional acidic residues have been constructed and characterized structurally and for enzymatic activity, revealing that their effect on activity is roughly inversely proportional to their distance from the heme and adduct, suggesting that the electrostatic potential of the heme cavity may be affected. A discrete group of protonable residues are contained within a 15 A sphere surrounding the heme iron, and a computational analysis reveals that the pKa of the distal His112, alone, is modulated within the pH range of catalase activity by the remote acidic residues in a pattern consistent with its protonated form having a key role in the catalase reaction cycle. The electrostatic potential also impacts the catalatic reaction through its influence on the charged status of the Met-Tyr-Trp adduct.
PDB ID: 5SYVDownload
MMDB ID: 143172
PDB Deposition Date: 2016/8/12
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 1.75  Å
Source Organism:
Similar Structures:
Biological Unit for 5SYV: dimeric; determined by author and by software (PISA)
Molecular Components in 5SYV
Label Count Molecule
Proteins (2 molecules)
2
Catalase-peroxidase
Molecule annotation
Chemicals (14 molecules)
1
2
2
2
3
2
4
2
5
5
6
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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