title: The PB1 domain and the PC motif-containing region are structurally similar protein binding modules.
abstract: The PC motif is evolutionarily conserved together with the PB1 domain, a binding partner of the PC motif-containing protein. For interaction with the PB1 domain, the PC motif-containing region (PCCR) comprising the PC motif and its flanking regions is required. Because the PB1 domain and the PCCR are novel binding modules found in a variety of signaling proteins, their structural and functional characterization is crucial. Bem1p and Cdc24p interact through the PB1-PCCR interaction and regulate cell polarization in budding yeast. Here, we determined a tertiary structure of the PCCR of Cdc24p by NMR. The tertiary structure of the PCCR is similar to that of the PB1 domain of Bem1p, which is classified into a ubiquitin fold. The PC motif portion takes a compact betabetaalpha-fold, presented on the ubiquitin scaffold. Mutational studies indicate that the PB1-PCCR interaction is mainly electrostatic. Based on the structural information, we group the PB1 domains and the PCCRs into a novel family, named the PB1 family. Thus, the PB1 family proteins form a specific dimer with each other.
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry; D020662:Guanine Nucleotide Exchange Factors; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000737:chemistry; D029701:Saccharomyces cerevisiae Proteins
chemical_list: C073594:CDC24 protein, S cerevisiae; D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; D011518:Proto-Oncogene Proteins; D029701:Saccharomyces cerevisiae Proteins