Topography for independent binding of alpha-helical and PPII-helical ligands to a peroxisomal SH3 domain.
While the function of most small signaling domains is confined to binary ligand interactions, the peroxisomal Pex13p SH3 domain has the unique capacity of binding to two different ligands, Pex5p and Pex14p. We have used this domain as a model to decipher its structurally independent ligand binding sites. By the combined use of X-ray crystallography, NMR spectroscopy, and circular dichroism, we show that the two ligands bind in unrelated conformations to patches located at opposite surfaces of this SH3 domain. Mutations in the Pex13p SH3 domain that abolish interactions within the Pex13p-Pex5p interface specifically impair PTS1-dependent protein import into yeast peroxisomes.
Douangamath
Alice
A
EMBL-Hamburg, c/o Deutsches Elektronen Synchrotron, Notkestrasse 85, D-22603 Hamburg, Germany.
Filipp
Fabian V
FV
Klein
André T J
AT
Barnett
Phil
P
Zou
Peijian
P
Voorn-Brouwer
Tineke
T
Vega
M Cristina
MC
Mayans
Olga M
OM
Sattler
Michael
M
Distel
Ben
B
Wilmanns
Matthias
M
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008565:Membrane Proteins / Q000737:chemistry*; D026901:Membrane Transport Proteins; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D000074401:Peroxins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000737:chemistry*; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014965:X-Rays; D018909:src Homology Domains
D002352:Carrier Proteins; D008024:Ligands; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C491105:PEX13 protein, S cerevisiae; C499195:PEX14 protein, S cerevisiae; D010455:Peptides; D000074401:Peroxins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins