PDBsum entry 2bf5

Oxidoreductase

PDB id: 2bf5

Contents

Protein chains

92 a.a. *

Waters ×238

* Residue conservation analysis

PDB id:

2bf5

Name:

Oxidoreductase

Title:

Crystal structure of a toluene 4-monooxygenase catalytic effector protein variant missing four n-terminal residues (delta-n4 t4mod)

Structure:

Toluene-4-monooxygenase system protein d. Chain: a, b. Fragment: residues 5-102. Synonym: delta-n4 toluene 4-monooxygenase catalytic effector. Engineered: yes

Source:

Pseudomonas mendocina. Organism_taxid: 300. Strain: kr1. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.71Å R-factor: 0.157 R-free: 0.185

Authors:

G.T.Lountos,K.H.Mitchell,J.M.Studts,B.G.Fox,A.M.Orville

Key ref:

G.T.Lountos et al. (2005). Crystal structures and functional studies of T4moD, the toluene 4-monooxygenase catalytic effector protein. Biochemistry, 44, 7131-7142. PubMed id: 15882052 DOI: 10.1021/bi047459g

Date:

03-Dec-04 Release date: 19-May-05

Protein chains

Q00459  (TMOD_PSEME) -  Toluene-4-monooxygenase system, effector component from Pseudomonas mendocina

Seq: 103 a.a.

Struc: 92 a.a.

Enzyme reactions

• Enzyme class: E.C.1.14.13.- - ?????

DOI no: 10.1021/bi047459g

Biochemistry 44:7131-7142 (2005)

PubMed id: 15882052

Crystal structures and functional studies of T4moD, the toluene 4-monooxygenase catalytic effector protein.

G.T.Lountos, K.H.Mitchell, J.M.Studts, B.G.Fox, A.M.Orville.

ABSTRACT

Toluene 4-monooxygenase (T4MO) is a four-component complex that catalyzes the regiospecific, NADH-dependent hydroxylation of toluene to yield p-cresol. The catalytic effector (T4moD) of this complex is a 102-residue protein devoid of metals or organic cofactors. It forms a complex with the diiron hydroxylase component (T4moH) that influences both the kinetics and regiospecificity of catalysis. Here, we report crystal structures for native T4moD and two engineered variants with either four (DeltaN4-) or 10 (DeltaN10-) residues removed from the N-terminal at 2.1-, 1.7-, and 1.9-A resolution, respectively. The crystal structures have C-alpha root-mean-squared differences of less than 0.8 A for the central core consisting of residues 11-98, showing that alterations of the N-terminal have little influence on the folded core of the protein. The central core has the same fold topology as observed in the NMR structures of T4moD, the methane monooxygenase effector protein (MmoB) from two methanotrophs, and the phenol hydroxylase effector protein (DmpM). However, the root-mean-squared differences between comparable C-alpha positions in the X-ray structures and the NMR structures vary from approximately 1.8 A to greater than 6 A. The X-ray structures exhibit an estimated overall coordinate error from 0.095 (0.094) A based on the R-value (R free) for the highest resolution DeltaN4-T4moD structure to 0.211 (0.196) A for the native T4moD structure. Catalytic studies of the DeltaN4-, DeltaN7-, and DeltaN10- variants of T4moD show statistically insignificant changes in k(cat), K(M), k(cat)/K(M), and K(I) relative to the native protein. Moreover, there was no significant change in the regiospecificity of toluene oxidation with any of the T4moD variants. The relative insensitivity to changes in the N-terminal region distinguishes T4moD from the MmoB homologues, which each require the approximately 33 residue N-terminal region for catalytic activity.