title: Evolutionary analyses of the 12-kDa acidic ribosomal P-proteins reveal a distinct protein of higher plant ribosomes.
abstract: The P-protein complex of eukaryotic ribosomes forms a lateral stalk structure in the active site of the large ribosomal subunit and is thought to assist in the elongation phase of translation by stimulating GTPase activity of elongation factor-2 and removal of deacylated tRNA. The complex in animals, fungi, and protozoans is composed of the acidic phosphoproteins P0 (35 kDa), P1 (11-12 kDa), and P2 (11-12 kDa). Previously we demonstrated by protein purification and microsequencing that ribosomes of maize (Zea mays L.) contain P0, one type of P1, two types of P2, and a distinct P1/P2 type protein designated P3. Here we implemented distance matrices, maximum parsimony, and neighbor-joining analyses to assess the evolutionary relationships between the 12 kDa P-proteins of maize and representative eukaryotic species. The analyses identify P3, found to date only in mono- and dicotyledonous plants, as an evolutionarily distinct P-protein. Plants possess three distinct groups of 12 kDa P-proteins (P1, P2, and P3), whereas animals, fungi, and protozoans possess only two distinct groups (P1 and P2). These findings demonstrate that the P-protein complex has evolved into a highly divergent complex with respect to protein composition despite its critical position within the active site of the ribosome.
authors.affiliation: Interdepartmental Graduate Program in Genetics, University of California, Riverside, CA 92521-0124, USA.
authors.forename: K
authors.initials: K
authors.lastname: Szick
authors.forename: M
authors.initials: M
authors.lastname: Springer
authors.forename: J
authors.initials: J
authors.lastname: Bailey-Serres
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D017124:Conserved Sequence; D019143:Evolution, Molecular; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012275:Oryza / Q000235:genetics; D010802:Phylogeny; D010944:Plants / Q000235:genetics*; D015800:Protozoan Proteins; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000235:genetics
chemical_list: C064601:L12E protein, Trypanosoma cruzi; D015800:Protozoan Proteins; D012269:Ribosomal Proteins