4B2N

Latex Oxygenase RoxA

Summary for 4B2N

• Entry DOI: 10.2210/pdb4b2n/pdb
• Descriptor: 70 KDA PROTEIN, HEME C, OXYGEN MOLECULE, ... (5 entities in total)
• Functional Keywords: electron transport, cytochrome, rubber oxygenase, dioxygenase
• Biological source: XANTHOMONAS SP.
• Total number of polymer chains: 2
• Total formula weight: 148896.24

Authors

Seidel, J.,Schmitt, G.,Hoffmann, M.,Jendrossek, D.,Einsle, O. (deposition date: 2012-07-17, release date: 2013-07-24, Last modification date: 2024-11-13)

Primary citation

Seidel, J.,Schmitt, G.,Hoffmann, M.,Jendrossek, D.,Einsle, O.
Structure of the processive rubber oxygenase RoxA from Xanthomonas sp.
Proc. Natl. Acad. Sci. U.S.A., 110:13833-13838, 2013

PubMed Abstract: Rubber oxygenase A (RoxA) is one of only two known enzymes able to catalyze the oxidative cleavage of latex for biodegradation. RoxA acts as a processive dioxygenase to yield the predominant product 12-oxo-4,8-dimethyl-trideca-4,8-diene-1-al (ODTD), a tri-isoprene unit. Here we present a structural analysis of RoxA from Xanthomonas sp. strain 35Y at a resolution of 1.8 Å. The enzyme is a 75-kDa diheme c-type cytochrome with an unusually low degree of secondary structure. Analysis of the heme group arrangement and peptide chain topology of RoxA confirmed a distant kinship with diheme peroxidases of the CcpA family, but the proteins are functionally distinct, and the extracellular RoxA has evolved to have twice the molecular mass by successively accumulating extensions of peripheral loops. RoxA incorporates both oxygen atoms of its cosubstrate dioxygen into the rubber cleavage product ODTD, and we show that RoxA is isolated with O2 stably bound to the active site heme iron. Activation and cleavage of O2 require binding of polyisoprene, and thus the substrate needs to use hydrophobic access channels to reach the deeply buried active site of RoxA. The location and nature of these channels support a processive mechanism of latex cleavage.

PubMed: 23922395
DOI: 10.1073/pnas.1305560110

Experimental method

X-RAY DIFFRACTION (1.8 Å)