Naslov
Crystal structure of a dodecameric FMN-dependent UbiX-like decarboxylase (Pad1) from Escherichia coli O157: H7

Autori
Rangarajan, E.S. ; Li, Y. ; Iannuzzi, P. ; Tocilj, Ante ; Hung, L.W. ; Matte, A. ; Cygler, M.

Izvornik
Protein science (0961-8368) 13 (2004), 11; 3006-3016

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, pregledni rad, znanstveni

Ključne riječi
Escherichia coli Crystal structure dodecameric decarboxylase

Sažetak
The crystal structure of the flavoprotein Pad1 from Escherichia coli O157:H7 complexed with the cofactor FMN has been determined by the multiple anomalous diffraction method and refined at 2.0 A resolution. This protein is a paralog of UbiX (3-octaprenyl-4-hydroxybenzoate carboxylyase, 51% sequence identity) that catalyzes the third step in ubiquinone biosynthesis and to Saccharomyces cerevisiae Pad1 (54% identity), an enzyme that confers resistance to the antimicrobial compounds phenylacrylic acids through decarboxylation of these compounds. Each Pad1 monomer consists of a typical Rossmann fold containing a non-covalently bound molecule of FMN. The fold of Pad1 is similar to MrsD, an enzyme associated with lantibiotic synthesis ; EpiD, a peptidyl-cysteine decarboxylase ; and AtHAL3a, the enzyme, which decarboxylates 4'-phosphopantothenoylcysteine to 4'-phosphopantetheine during coenzyme A biosynthesis, all with a similar location of the FMN binding site at the interface between two monomers, yet each having little sequence similarity to one another. All of these proteins associate into oligomers, with a trimer forming the common structural unit in each case. In MrsD and EpiD, which belong to the homo-dodecameric flavin-containing cysteine decarboxylase (HFCD) family, these trimers associate further into dodecamers. Pad1 also forms dodecamers, although the association of the trimers is completely different, resulting in exposure of a different side of the trimer unit to the solvent. This exposure affects the location of the substrate binding site and, specifically, its access to the FMN cofactor. Therefore, Pad1 forms a separate family, distinguishable from the HFCD family.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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