4ENU

Structure of the S234D variant of E. coli KatE

Summary for 4ENU

• Entry DOI: 10.2210/pdb4enu/pdb
• Related: 4ENP 4ENQ 4ENR 4ENS 4ENT 4ENV 4ENW
• Descriptor: Catalase HPII, CIS-HEME D HYDROXYCHLORIN GAMMA-SPIROLACTONE (3 entities in total)
• Functional Keywords: catalase fold, kate, s234d variant, oxidoreductase
• Biological source: Escherichia coli
• Cellular location: Cytoplasm (Probable): P21179
• Total number of polymer chains: 4
• Total formula weight: 339919.79

Authors

Loewen, P.C.,Jha, V. (deposition date: 2012-04-13, release date: 2012-05-02, Last modification date: 2013-02-27)

Primary citation

Jha, V.,Chelikani, P.,Carpena, X.,Fita, I.,Loewen, P.C.
Influence of main channel structure on H(2)O(2) access to the heme cavity of catalase KatE of Escherichia coli.
Arch.Biochem.Biophys., 526:54-59, 2012

PubMed Abstract: The main channel for H(2)O(2) access to the heme cavity in large subunit catalases is twice as long as in small subunit catalases and is divided into two distinct parts. Like small subunit catalases, the 15Å of the channel adjacent to the heme has a predominantly hydrophobic surface with only weak water occupancy, but the next 15Å extending to the protein surface is hydrophilic and contains a complex water matrix in multiple passages. At the approximate junction of these two sections are a conserved serine and glutamate that are hydrogen bonded and associated with H(2)O(2) in inactive variants. Mutation of these residues changed the dimensions of the channel, both enlarging and constricting it, and also changed the solvent occupancy in the hydrophobic, inner section of the main channel. Despite these structural changes and the prominent location of the residues in the channel, the variants exhibited less than a 2-fold change in the k(cat) and apparent K(M) kinetic constants. These results reflect the importance of the complex multi-passage structure of the main channel. Surprisingly, mutation of either the serine or glutamate to an aliphatic side chain interfered with heme oxidation to heme d.

PubMed: 22820098
DOI: 10.1016/j.abb.2012.06.010

Experimental method

X-RAY DIFFRACTION (1.7 Å)