Sites for interaction between Gal80p and Gal1p in Kluyveromyces lactis: structural model of galactokinase based on homology to the GHMP protein family

R A Menezes; C Amuel; R Engels; U Gengenbacher; J Labahn; C P Hollenberg

doi:10.1016/j.jmb.2003.08.034

Sites for interaction between Gal80p and Gal1p in Kluyveromyces lactis: structural model of galactokinase based on homology to the GHMP protein family

J Mol Biol. 2003 Oct 24;333(3):479-92. doi: 10.1016/j.jmb.2003.08.034.

Authors

R A Menezes¹, C Amuel, R Engels, U Gengenbacher, J Labahn, C P Hollenberg

Affiliation

¹ Institut für Mikrobiologie and Biologisch-Medizinisches Forschungszentrum, Heinrich-Heine-Universität, Universitätsstr. 1, D-40225, Düsseldorf, Germany.

PMID: 14556739
DOI: 10.1016/j.jmb.2003.08.034

Abstract

The induction of transcription of the galactose genes in yeast involves the galactose-dependent binding of ScGal3p (in Saccharomyces cerevisiae) or KlGal1p (in Kluyveromyces lactis) to Gal80p. This binding abrogates Gal80's inhibitory effect on the activation domain of Gal4p, which can then activate transcription. Here, we describe the isolation and characterization of new interaction mutants of K.lactis GAL1 and GAL80 using a two-hybrid screen. We present the first structural model for Gal1p to be based on the published crystal structures of other proteins belonging to the GHMP (galactokinase, homoserine kinase, mevalonate kinase and phosphomevalonate kinase) kinase family and our own X-ray diffraction data of Gal1p crystals at 3A resolution. The locations of the various mutations in the modelled Gal1p structure identify domains involved in the interaction with Gal80p and provide a structural explanation for the phenotype of constitutive GAL1 mutations.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Bacterial Proteins / chemistry*
Bacterial Proteins / genetics
Bacterial Proteins / metabolism*
Binding Sites
Crystallography, X-Ray
Galactokinase / chemistry*
Galactokinase / genetics
Galactokinase / metabolism*
Kluyveromyces / chemistry
Kluyveromyces / metabolism*
Models, Molecular
Molecular Sequence Data
Multigene Family
Mutation / genetics
Protein Binding
Protein Structure, Tertiary
Repressor Proteins / chemistry
Repressor Proteins / genetics
Repressor Proteins / metabolism
Saccharomyces cerevisiae Proteins / chemistry
Saccharomyces cerevisiae Proteins / genetics
Saccharomyces cerevisiae Proteins / metabolism
Sequence Alignment
Sequence Homology, Amino Acid
Structure-Activity Relationship
Suppression, Genetic / genetics
Transcription Factors / chemistry*
Transcription Factors / genetics
Transcription Factors / metabolism*
Two-Hybrid System Techniques

Substances

Bacterial Proteins
GAL80 protein, S cerevisiae
Gal3 protein, S cerevisiae
Repressor Proteins
Saccharomyces cerevisiae Proteins
Transcription Factors
Galactokinase