PDBsum entry 3e2n

Oxidoreductase

PDB id: 3e2n

Contents

Protein chain

282 a.a. *

Ligands

HEM

Waters ×589

* Residue conservation analysis

PDB id:

3e2n

Name:

Oxidoreductase

Title:

Engineering ascorbate peroxidase activity into cytochromE C peroxidase

Structure:

CytochromE C peroxidase. Chain: a. Fragment: unp residues 68-361, see remark 999. Synonym: ccp. Engineered: yes. Mutation: yes

Source:

Saccharomyces cerevisiae, pisum sativum. Garden pea. Organism_taxid: 4932, 3888. Gene: ccp1, ccp, cpo, ykr066c, apx1,appx1. Expressed in: escherichia coli.

Resolution:

1.30Å R-factor: 0.181

Authors:

T.L.Poulos,Y.T.Meharenna,P.Oertel

Key ref:

Y.T.Meharenna et al. (2008). Engineering ascorbate peroxidase activity into cytochrome c peroxidase. Biochemistry, 47, 10324-10332. PubMed id: 18771292

Date:

05-Aug-08 Release date: 21-Oct-08

Protein chain

P00431  (CCPR_YEAST) -  Cytochrome c peroxidase, mitochondrial from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 361 a.a.

Struc: 282 a.a.*

Protein chain

P48534  (APX1_PEA) -  L-ascorbate peroxidase, cytosolic from Pisum sativum

Seq: 250 a.a.

Struc: 282 a.a.*

* PDB and UniProt seqs differ at 165 residue positions (black crosses)

Enzyme reactions

• Enzyme class 1: E.C.1.11.1.11 - L-ascorbate peroxidase.
• Reaction: L-ascorbate + H2O2 = L-dehydroascorbate + 2 H2O
• Cofactor: Heme

Heme (Bound ligand (Het Group name = HEM) matches with 95.45% similarity)

• Enzyme class 2: E.C.1.11.1.5 - cytochrome-c peroxidase.
• Reaction: 2 Fe(II)-[cytochrome c] + H2O2 + 2 H⁺ = 2 Fe(III)-[cytochrome c] + 2 H2O
• Cofactor: Heme

Heme (Bound ligand (Het Group name = HEM) matches with 95.45% similarity)

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Biochemistry 47:10324-10332 (2008)

PubMed id: 18771292

Engineering ascorbate peroxidase activity into cytochrome c peroxidase.

Y.T.Meharenna, P.Oertel, B.Bhaskar, T.L.Poulos.

ABSTRACT

Cytochrome c peroxidase (CCP) and ascorbate peroxidase (APX) have very similar structures, and yet neither CCP nor APX exhibits each other's activities with respect to reducing substrates. APX has a unique substrate binding site near the heme propionates where ascorbate H-bonds with a surface Arg and one heme propionate (Sharp et al. (2003) Nat. Struct. Biol. 10, 303-307). The corresponding region in CCP has a much longer surface loop, and the critical Arg residue that is required for ascorbate binding in APX is Asn in CCP. In order to convert CCP into an APX, the ascorbate-binding loop and critical arginine were engineered into CCP to give the CCP2APX mutant. The mutant crystal structure shows that the engineered site is nearly identical to that found in APX. While wild-type CCP shows no APX activity, CCP2APX catalyzes the peroxidation of ascorbate at a rate of approximately 12 min (-1), indicating that the engineered ascorbate-binding loop can bind ascorbate.