Publication

The moonlighting function of pyruvate carboxylase resides in the non-catalytic end of the TIM barrel

Huberts, D. H. E. W., Venselaar, H., Vriend, G., Veenhuis, M. & van der Klei, I. J., Sep-2010, In : Biochimica et Biophysica Acta-Molecular Cell Research. 1803, 9, p. 1038-1042 5 p.

Research output: Contribution to journalArticleAcademicpeer-review

Copy link to clipboard

Documents

DOI

Pyruvate carboxylase is a highly conserved enzyme that functions in replenishing the tricarboxylic acid cycle with oxaloacetate. In the yeast Hansenula polymorpha, the pyruvate carboxylase protein is also required for import and assembly of the peroxisomal enzyme alcohol oxidase. This additional role, which is unrelated to the enzyme activity, represents an example of a special form of multifunctionality called moonlighting. We have performed a detailed site-directed mutagenesis approach to elucidate which region(s) of H. polymorpha pyruvate carboxylase are involved in its second function. This resulted in the identification of three amino acids that are essential for the moonlighting function. Mutating these residues in a single mutant protein fully inactivated the moonlighting function, but not the enzyme activity of pyruvate carboxylase because the strain was prototrophic. A 3D homology model revealed that all three residues are positioned at the side of a TIM barrel where the N-terminal ends of the beta-strands are located. This is a novel observation as the TIM barrel proteins invariably are enzymes and have their catalytic side at the C-terminal end of the beta-sheets. Our finding implies that a TIM barrel fold can also fulfill a non-enzymatic function and that this function can reside at the N-terminal end of the barrel. (C) 2010 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)1038-1042
Number of pages5
JournalBiochimica et Biophysica Acta-Molecular Cell Research
Volume1803
Issue number9
Publication statusPublished - Sep-2010

    Keywords

  • Pyruvate carboxylase, Moonlighting protein, TIM barrel, Alcohol oxidase, Peroxisome, YEAST HANSENULA-POLYMORPHA, ALCOHOL OXIDASE, SACCHAROMYCES-CEREVISIAE, PEROXISOME BIOGENESIS, METHANOL METABOLISM, PROTEINS, MUTANT

Download statistics

No data available

ID: 1918603