A comparison of the alanine‐rich sequences of the L7/L12‐ribosomal proteins from rat liver, Artemia salina and Escherichia coli, with the amino‐terminal region of the alkali light chain A1 from rabbit myosin

Amons, Reinout; Agthoven, André Van; Pluijms, W.; Möller, W.

doi:10.1016/0014-5793(78)80580-8

Cited by 20 publications

(6 citation statements)

References 18 publications

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“…Amino acid sequence analysis of acidic proteins from ribosomes of archaebacterial and eukaryotic organisms indicates structural similarity with the E. coli acidic proteins L7/L12 (12,34,35). Preliminary experiments suggest their presence in multiple copies and functional assays have pointed to their involvement in GTP-related processes (13)(14)(15).…”

Section: Discussionmentioning

confidence: 99%

Topography and stoichiometry of acidic proteins in large ribosomal subunits from Artemia salina as determined by crosslinking.

Uchiumi¹,

Wahba²,

Traut³

1987

Proc. Natl. Acad. Sci. U.S.A.

127

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The 60S subunits isolated fromArtemia salina ribosomes were treated with the crosslinking reagent 2-iminothiolane under mild conditions. Proteins were extracted and fractions containing crosslinked acidic proteins were obtained by stepwise elution from CM-cellulose. Each fraction was analyzed by "diagonal" (two-dimensional nonreducing-reducing) NaDodSO4/polyacrylamide gel electrophoresis. Crosslinked proteins below the diagonal were radioiodinated and identified by two-dimensional acidic urea-NaDodSO4 gel electrophoresis. Each of the acidic proteins P1 and P2 was crosslinked individually to the same third protein, P0. The fractions containing acidic proteins were also analyzed by two-dimensional nonequilibrium isoelectric focusing-NaDod-S04/polyacrylamide gel electrophoresis. Two crosslinked complexes were observed that coincide in isoelectric positions with monomeric P1 and P2, respectively. Both P1 and P2 appear to form crosslinked homodimers. These results suggest the presence in the 60S subunit of (P1)2 and (P2)2 dimers, each of which is anchored to P0. Protein PO appears to play the same role as L10 in Escherichia coli ribosomes and may form a pentameric complex with the two dimers in the 60S subunits.The large ribosomal subunits of Escherichia coli contain multiple copies of a protein, L7/L12, that is present as two dimers, each of which is anchored to the ribosome through interaction with a common protein, L10 (1-4). The four copies of L7/L12 are easily and selectively removed from the ribosome and can be reconstituted (5). The proteins are involved in the GTP-dependent reactions of protein synthesis-in particular, translocation (6-8). A model has been proposed recently, showing different orientation for the two L7/L12 dimers on the ribosome surface (9).The large subunits of eukaryotic ribosomes also contain multicopy acidic proteins (10, 11) that are structurally and functionally related to L7/L12 (12-15). These proteins exist in phosphorylated states and have been designated P proteins (16-18). Two different P proteins having slightly different amino acid compositions, electrophoretic mobilities, and molecular weights have been designated P1 and P2 (16). Anti-ribosome antibodies from certain patients with systemic lupus erythematosus react exclusively with P1 and P2 and, in addition, with a third acidic protein designated PO (19,20). These three proteins also react with a mouse monoclonal antibody raised against chicken ribosomes (17).The spatial arrangement of the P proteins in the eukaryotic ribosome is not yet well established. We have investigated the topography of P1 and P2 [designated eL12' and eL12 in Artemia ribosomes (10) Elution of the proteins from CM-cellulose at pH 5.0 (6 M urea/10 mM sodium acetate/0.1% methylamine/3 mM iodoacetamide, adjusted to pH 5.0 with acetic acid) instead of pH 7.2 was also used for some experiments.Abbreviations: P proteins, eukaryotic ribosomal proteins PO, P1, and P2; NEPHGE, nonequilibrium pH gradient electrophoresis.tPresent address:

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Section: Discussionmentioning

confidence: 99%

Topography and stoichiometry of acidic proteins in large ribosomal subunits from Artemia salina as determined by crosslinking.

Uchiumi¹,

Wahba²,

Traut³

1987

Proc. Natl. Acad. Sci. U.S.A.

127

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“…In addition to the similarities noted between protein A and actin and myosin Al light chain, Escherichia coli L7/L12 ribosomal proteins (41) have been shown to have sequence similarities with myosin (Al light chain). Also, the repetitive sequence and conformational properties of E. coli lipoprotein (42) have led to a suggestion that it may be similar to tropomyosin.…”

Section: Fig 1 (Upper)mentioning

confidence: 98%

Amino acid sequence and physicochemical similarities between streptococcal M protein and mammalian tropomyosin.

Hosein¹,

McCarty²,

Fischetti³

1979

Proc. Natl. Acad. Sci. U.S.A.

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ABSTRACr-The amino-terminal sequences of two peptides of type 24 streptococcal M protein show similarities with that of rabbit skeletal muscle tropomyosin, having up to 40% identical residues and probabilities of occurring by chance as low as P < 10-5. In addition, a hexapeptide (Glu-Ala-Glu-Lys-AlaAla) that is found five times in the M24 protein was shown to be identical to a sequence in tropomyosin. Similarities are also seen in the amino acid compositions and physicochemical properties of tfie two proteins. The amino-terminal sequences of peptides from another bacterial surface protein, staphylococcal protein A, are highly correlated with segments of two other myofibrillar proteins, rabbit actin (P < 10-7) and rabbit myosin Al light chain (P < 10-6). The data presented suggest that a close structural relationship exists between mammalian muscle proteins and the biologically active surface proteins of staphylococci and streptococci. In addition, the correlation between sequences in M protein and tropomyosin represents direct evidence of a structural similarity at a molecular level between a streptococcal protein and a mammalian muscle component and may therefore prove relevant to the pathogenicity of the streptococcus.Group A streptococci possess antiphagocytic surface antigens, known as M proteins, that are primarily responsible for the virulence of these organisms (1). Based on extensive immunological data, it has been clearly shown that resistance to streptococcal infection is dependent on neutralization of the antiphagocytic effect of M proteins by type-specific opsonic antibodies (1, 2). Immunological cross reactions do occur' between certain of the more than 70 immunologically distinct M types (3, 4), but the antibodies involved rarely afford crossprotection (3). Recent peptide analyses (5) and sequence studies (6, 7) on a limited number of M protein types revealed that, in spite of a common biological activity, M proteins are composed of different primary structures. Despite these immunological and structural differences, all M protein molecules studied to date share certain noteworthy chemical and physical properties (8). Their extreme thermal stability (9), their highly elongated shape (10, 11), and their appearance as a network of projections on streptococcal cell walls (12) suggested that M proteins might have properties in common with previously characterized fibrous proteins.This report describes striking chemical, physical, and sequence similarities between streptococcal M protein and rabbit skeletal muscle tropomyosin. In addition, computer analysis of the partial sequence of staphylococcal protein A, another biologically active, Gram-positive, surface protein, having properties in common with M protein, reveals significant homology with two other myofibrillar proteins, actin and myosin Al light chain.

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“…While the bacterial L12 proteins comprise a highly homologous assembly, the archaeal variants are related to the eukaryotic representatives and there is little similarity discernible between the bacterial and archaeal/eukaryotic groups [7,9,30,[81][82][83]. It has been generally observed that the information-processing machineries of archaea are more related to eukarya than bacteria [30] and interestingly, the first sign of these relationships in ribosomes came from sequence comparisons of r-proteins [81,84,85] rather than rRNA. On the other hand, the domain organization, featuring a functionally separable NTD, a connecting hinge region, and a CTD (see Domain Organization and Structures), seems to have been preserved in all species [28].…”

Section: Phylogenetic Comparisonsmentioning

confidence: 99%

Structure and Function of the Acidic Ribosomal Stalk Proteins

Wahl

Möller²

2002

curr protein pept sci

105

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The acidic L7/L12 (prokaryotes) and P1/P2 (eukaryotes) proteins are the only ribosomal components that occur in more than one, specifically four, copies in the translational machinery. These ribosomal proteins are the only ones that do not directly interact with ribosomal RNA but bind to the particles via a protein, L10 and P0, respectively. They constitute a morphologically distinct feature on the large subunit, the stalk protuberance. Since a long time proteins L7/L12 have been implicated in translation factor binding and in the stimulation of the factor-dependent GTP-hydrolysis. Recent studies reproduced such activities with the isolated components and L7/L12 can therefore in retrospect be regarded as the first GTPase activating proteins identified. GTP-hydrolysis induces a drastic conformational change in elongation factor (EF) Tu, which enables it to dissociate from the ribosome after having successfully delivered aminoacylated tRNA into the A-site. It is also used as a driving force for translocation, mediated by EF-G. The in vitro stimulation of translation-uncoupled EF-G-dependent GTP-hydrolysis seems to be an intrinsic property of the ribosome that is dependent on L7/L12, reaches a maximum with four copies of the proteins per particle, and reflects the in vivo hydrolysis rate during translation. It is much larger than the analogous activity observed for EF-Tu, which is correlated with the in vitro polypeptide synthesis rate. Therefore, at least certain stimulatory activities of L7/L12 are controlled by the ribosomal environment, which in the case of EF-Tu senses the successful codon-anticodon pairing. Present knowledge is consistent with a picture in which proteins L7/L12 constitute a "landing platform" for the factors and after rearrangements induce GTP-hydrolysis. The molecular mechanism of the GTPase activation is unknown. While sequence comparisons show a large diversity in the stalk proteins across the kingdoms, a conserved functional domain organization and conserved designs of their genetic units are discernible. Consistently, stalk transplantation experiments suggest that coevolution took place to maintain functional L7/L12 EF-G and P-protein EF-2 couples. The acidic proteins are organized into three distinct functional parts: An N-terminal domain is responsible for oligomerization and ribosome association, a C-terminal domain is implicated in translation factor interactions, and a hinge region allows a flexible relative orientation of the latter two portions. The bacterial L7/L12 proteins have long been portrayed as highly elongated dimers displaying globular C-terminal domains, helical N-termini, and unstructured hinges. Conversely, recent crystal structures depict a compact hetero-tetrameric assembly with the hinge region adopting either an alpha-helical or an open conformation. Two different dimerization modes can be discerned in these structures. Models suggest that dimerization via one association mode can lead to elongated dimeric complexes with one helical and one unstructured hinge. The ...

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A comparison of the alanine‐rich sequences of the L7/L12‐ribosomal proteins from rat liver, Artemia salina and Escherichia coli, with the amino‐terminal region of the alkali light chain A₁ from rabbit myosin

Cited by 20 publications

References 18 publications

Topography and stoichiometry of acidic proteins in large ribosomal subunits from Artemia salina as determined by crosslinking.

Topography and stoichiometry of acidic proteins in large ribosomal subunits from Artemia salina as determined by crosslinking.

Amino acid sequence and physicochemical similarities between streptococcal M protein and mammalian tropomyosin.

Structure and Function of the Acidic Ribosomal Stalk Proteins

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