Analysis of the pore of the unusual major intrinsic protein channel, yeast Fps1p.
Artikel i vetenskaplig tidskrift, 2001

Fps1p is a glycerol efflux channel from Saccharomyces cerevisiae. In this atypical major intrinsic protein neither of the signature NPA motifs of the family, which are part of the pore, is preserved. To understand the functional consequences of this feature, we analyzed the pseudo-NPA motifs of Fps1p by site-directed mutagenesis and assayed the resultant mutant proteins in vivo. In addition, we took advantage of the fact that the closest bacterial homolog of Fps1p, Escherichia coli GlpF, can be functionally expressed in yeast, thus enabling the analysis in yeast cells of mutations that make this typical major intrinsic protein more similar to Fps1p. We observed that mutations made in Fps1p to "restore" the signature NPA motifs did not substantially affect channel function. In contrast, when GlpF was mutated to resemble Fps1p, all mutants had reduced activity compared with wild type. We rationalized these data by constructing models of one GlpF mutant and of the transmembrane core of Fps1p. Our model predicts that the pore of Fps1p is more flexible than that of GlpF. We discuss the fact that this may accommodate the divergent NPA motifs of Fps1p and that the different pore structures of Fps1p and GlpF may reflect the physiological roles of the two glycerol facilitators.

Escherichia coli

metabolism

metabolism

Time Factors

Amino Acid Motifs

Immunoblotting

Membrane Proteins

Protein Structure

metabolism

Escherichia coli Proteins

Saccharomyces cerevisiae

Glycerol

Point Mutation

Mutation

Tertiary

chemistry

Saccharomyces cerevisiae Proteins

DNA Primers

metabolism

Mutagenesis

Aquaporins

Fungal Proteins

Plasmids

Cell Membrane

chemistry

chemistry

Molecular

Site-Directed

metabolism

Models

Bacterial Outer Membrane Proteins

metabolism

Protein Binding

Författare

R Bill

Göteborgs universitet

Kristina Hedfalk

Chalmers, Institutionen för kemi och biovetenskap

S Karlgren

J G Mullins

J Rydström

S Hohmann

Journal of Biological Chemistry

0021-9258 (ISSN) 1083-351X (eISSN)

Vol. 276 36543-9

Ämneskategorier

Biologiska vetenskaper

DOI

10.1074/jbc.M105045200

PubMed

11445582