Amino-terminal processing of proteins: hemoglobin South Florida, a variant with retention of initiator methionine and N alpha-acetylation.

Boissel, J. P.; Kasper, TJ; Shah, Shirish C.; Malone, John I.; Bunn, H. Franklin

doi:10.1073/pnas.82.24.8448

Cited by 106 publications

(50 citation statements)

References 39 publications

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“…However, mass spectrometry data on the intact native nerve globin showed a molecular mass of 18,235 Da, which confirms the absence of the N-terminal methionine and suggests an N-terminal mono-acetylation (ϩ42 Da). This is not so unusual as N-terminal acetylation is one of the most common protein modifications in eukaryotes, occurring on ϳ85% of the different varieties of eukaryotic proteins but rarely on prokaryotic proteins (43,44). We observed two additional molecular mass classes (18,333 and 18,430 Da) that differ from the native mono-acetylated protein by 98 and 196 Da, respectively (Fig.…”

Section: Resultsmentioning

confidence: 71%

The Nerve Hemoglobin of the Bivalve Mollusc Spisula solidissima

Dewilde

Ebner

Vinck

et al. 2006

Journal of Biological Chemistry

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Members of the hemoglobin (Hb) superfamily are present in nerve tissue of several vertebrate and invertebrate species. In vertebrates they display hexacoordinate heme iron atoms and are typically expressed at low levels (M). Their function is still a matter of debate. In invertebrates they have a hexa-or pentacoordinate heme iron, are mostly expressed at high levels (mM), and have been suggested to have a myoglobin-like function. The native Hb of the surf clam, Spisula solidissima, composed of 162 amino acids, does not show specific deviations from the globin templates. UV-visible and resonance Raman spectroscopy demonstrate a hexacoordinate heme iron. Based on the sequence analogy, the histidine E7 is proposed as a sixth ligand. Kinetic and equilibrium measurements show a moderate oxygen affinity (P 50 ϳ0.6 torr) and no cooperativity. The histidine binding affinity is 100-fold lower than in neuroglobin. Phylogenetic analysis demonstrates a clustering of the S. solidissima nerve Hb with mollusc Hbs and myoglobins, but not with the vertebrate neuroglobins. We conclude that invertebrate nerve Hbs expressed at high levels are, despite the hexacoordinate nature of their heme iron, not essentially different from other intracellular Hbs. They most likely fulfill a myoglobin-like function and enhance oxygen supply to the neurons.The recent discovery of globin proteins in the nerve cells of mammals and other vertebrates (1) has created much interest in unraveling the cellular functions and potential biomedical implications of these oxygen binding molecules in the metabolism of the vertebrate nervous system (2). Historically, however, "nerve hemoglobins" (nHbs) 4 were first observed in invertebrate taxa. In 1872, Lankester had already recorded the brilliant red color of the ganglia of the polychaete annelid Aphrodite aculeata (3). Since then, nHbs have also been found in, or associated with, nerve tissues of several other invertebrate taxa, such as molluscs, arthropods, nemerteans, and nematode species (4, 5). Of these, only the nHbs of A. aculeata (6) and the nemertean worm Cerebratulus lacteus (7) have been characterized at the molecular level.With few exceptions (e.g. in air-breathing gastropods), the invertebrate nHbs are expressed at high concentrations (in the mM range) and have therefore been suggested to support nerve function by mediating O 2 storage and/or transport during temporary hypoxia (4). For example, in the gastropod mollusc Aplysia depilans, the oxygenation state of the nHb was correlated with the electrical activity of the neural ganglia, and firing was shown to be proportional to the degree of oxygenation of the globin (8). The nHb in the nerve bundles of the bivalve mollusc Tellina alternata was reported to extend the time of O 2 delivery to the nerves during anoxic periods by as much as 30 min, whereas this effect was not demonstrable in the nerves of a related clam species Tagelius plebeius, which lack the nHb (9). In many cases, the nHbs appear to be specifically expressed in the glial cells surr...

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Section: Resultsmentioning

confidence: 71%

The Nerve Hemoglobin of the Bivalve Mollusc Spisula solidissima

Dewilde

Ebner

Vinck

et al. 2006

Journal of Biological Chemistry

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“…This commonly occurs in protein where the second amino acid is small and neutral. 31 Amino terminal modification is required for the function of alpha-tropomyosin in striated muscle 32 and modifies actin function in Drosophila. 33 The distinct difference in adseverin expression seen between Lin Ϫ Sca ϩ Kit ϩ and Lin Ϫ Sca ϩ Kit Ϫ cells suggests that there is a potential difference in regulation of actin filaments and thereby motility.…”

Section: Resultsmentioning

confidence: 99%

Comparative proteomics of primitive hematopoietic cell populations reveals differences in expression of proteins regulating motility

Evans

Tonge²,

Blinco³

et al. 2004

Blood

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Lineage-marker depleted (Lin ؊ ) murine bone marrow cells expressing stem cell antigen 1 (Sca-1) were sorted on the basis of stem cell factor receptor (c-kit) expression to obtain Lin ؊ Sca ؉ Kit ؉ or Lin ؊ Sca ؉ Kit ؊ cells. Lin ؊ Sca ؉ Kit ؊ cells have a markedly greater chemotactic response to stromal derived factor-1 (SDF-1). Using a novel fluorescent stain, we show that both populations generate similar levels of a key messenger, phosphatidylinositol 3,4,5 trisphosphate (PIP 3 ), in response to SDF-1. Differences in motile behavior may therefore lie downstream of phosphatidylinositol 3-kinase (PI3-kinase) activation at the level of cytoskeleton regulation. The 2 cell populations were compared using 2-dimensional difference gel electrophoresis (2D-DIGE), with a maleimide CyDye fluorescent protein labeling technique that has enhanced sensitivity for low abundance samples. Comparative proteomic analysis of Cy3-and Cy5-labeled protein samples allows relative quantification of protein spots present in both cell populations; of these, 73% were common. Key protein differences were adseverin and gelsolin, actin microfilament splicing proteins, regulated by Rac, downstream of PI3-kinase activation. Adseverin was shown to be acetylated, a novel modification for this protein. Differences in major regulators of cell shape and motility between the 2 populations can explain the differential response to SDF-1. IntroductionHematopoietic stem cells have the capacity to self-renew and also to differentiate to form a number of mature cell types with distinct morphologies and functional activities. The distinctive features of the stem cell that give it longevity and the ability to balance its self-renewal and differentiation to the required degree in any circumstance remain unclear. These biologic properties are encoded in the transcriptional profile, or transcriptome, of stem cells. The properties of a stem cell can therefore be defined in terms of the gene expression profiles of stem cells. Retention of stem cell characteristics will rely in part on the cohort of genes specifically expressed in these primitive cells, but not in their maturing progeny. This axiom has led to transcriptional analysis of long-and short-term repopulating stem cells and other primitive populations (defined via expression of specific markers) to define the genes expressed for self-renewal and pluripotency. 1,2 The generation of these stem cell "blueprints" then offers the opportunity to investigate the functional activity of the proteins produced as a consequence of gene expression and to systematically study gene networks controlling stem cell biology.The relationship between messenger RNA production and protein synthesis is not, however, strictly correlative. 3 In a range of different organisms it has become clear that changes in the expression of a specific protein do not necessarily relate directly to altered transcription. Recent developments in protein separation and relative quantification allow populations of cells to be compared at the pr...

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“…From a systematic analysis of the amino-terminal sequences data for various mutant forms of yeast iso-1-cytochrome c, as well as from the data for 82 mature intracellular proteins, Sherman et al (28) concluded that the MAPs from various procaryotes and eucaryotes share similar substrate specificity. Surveys of the protein sequence data bank by Boissel et al (4) and Sherman et al (28) provided similar deduced general sequence features in amino-terminal methionine processing.…”

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confidence: 99%

Processing of the initiation methionine from proteins: properties of the Escherichia coli methionine aminopeptidase and its gene structure

Ben‐Bassat¹,

Bauer²,

Chang³

et al. 1987

J Bacteriol

493

305

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Methionine aminopeptidase (MAP) catalyzes the removal of amino-terminal methionine from proteins. The Escherichia coli map gene encoding this enzyme was cloned; it consists of 264 codons and encodes a monomeric enzyme of 29,333 daltons. In vitro analyses with purified enzyme indicated that MAP is a metallooligopeptidase with absolute specificity for the amino-terminal methionine. The methionine residues from the amino-terminal end of the recombinant proteins interleukin-2 (Met-Ala-Pro-IL-2) and ricin A (Met-Ile-Phericin A) could be removed either in vitro with purified MAP enzyme or in vivo in MAP-hyperproducing strains of E. coli. In vitro analyses of the substrate preference of the E. coli MAP indicated that the residues adjacent to the initiation methionine could significantly influence the methionine cleavage process. This conclusion is consistent, in general, with the deduced specificity of the enzyme based on the analysis of known aminoterminal sequences of intracellular proteins (S. Tsunasawa, J. W. Stewart, and F. Sherman, J. Biol. Chem. 260:5382-5391, 1985).Protein synthesis is always initiated with either methionine or N-formylmethionine. The N-formyl moiety that is present on proteins from organelles and bacteria is removed by deformylases, leaving methionine at the amino terminus. For a significant fraction of the intracellular proteins, the amino-terminal methionine is removed enzymatically after the initiation of translation (1,2,5,10,24,33,34,38,40; for a review, see reference 28). Although other mechanisms may also be involved in the post-or cotranslational modifications of the amino-terminal residues of some proteins (e.g., signal peptidases that remove the secretory signal peptide sequences from certain transported proteins, transacetylases that acetylate the amino-terminal residues of some eucaryotic proteins), methionine is removed from the majority of proteins. However, very little is known about the structure and properties of the methionine aminopeptidase (MAP) that is responsible for removing the amino-terminal methionine residue from the cellular proteins. From a systematic analysis of the amino-terminal sequences data for various mutant forms of yeast iso-1-cytochrome c, as well as from the data for 82 mature intracellular proteins, Sherman et al. (28) For Escherichia coli and Salmonella typhimurium, many peptidase genes have been mapped, and their cognate peptidases have been characterized (6,9,22,23,29,30,32,35,36). However, none reported so far corresponds to the activity postulated for MAP. We took a direct approach to study the MAP of E. coli by molecular cloning of its gene (map) and identified the gene based on the postulated properties of the gene product. An E. coli strain deficient in five peptidases was transformed with a plasmid preparation * Corresponding author. containing a library of cloned genomic DNA fragments from the same strain. The lysates from individual transformants were then prepared and analyzed for the presence of elevated MAP activity. This allowed us to i...

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Amino-terminal processing of proteins: hemoglobin South Florida, a variant with retention of initiator methionine and N alpha-acetylation.

Cited by 106 publications

References 39 publications

The Nerve Hemoglobin of the Bivalve Mollusc Spisula solidissima

The Nerve Hemoglobin of the Bivalve Mollusc Spisula solidissima

Comparative proteomics of primitive hematopoietic cell populations reveals differences in expression of proteins regulating motility

Processing of the initiation methionine from proteins: properties of the Escherichia coli methionine aminopeptidase and its gene structure

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