HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ruoppolo, M. Articles by Esposito, C. Search for Related Content PubMed PubMed Citation Articles by Ruoppolo, M. Articles by Esposito, C. Social Bookmarking                   What's this?

Structural characterization of transglutaminase-catalyzed cross-linking between glyceraldehyde 3-phosphate dehydrogenase and polyglutamine repeats

¹ Dipartimento di Chimica, Università di Salerno, Salerno, Italy
² Dipartimento di Pediatria, Università di Napoli "Federico II," Naples, Italy

Reprint requests to: Carla Esposito, Dipartimento di Chimica, Università di Salerno, Via S. Allende, 84081 Baronissi, Salerno, Italy; e-mail: cesposito{at}unisa.it; fax: 0039-089-965296.

The accumulation of abnormal polyglutamine-containing protein aggregates within the cytosol and nuclei of affected neurons is a hallmark of the progressive neurodegenerative disorders caused by an elongated (CAG)_n repeat in the genome. The polyglutamine domains are excellent substrates for the enzyme transglutaminase type 2 (tissue), resulting in the formation of cross-links with polypeptides containing lysyl groups. Enzymatic activity toward the Q_n domains increases greatly upon lengthening of such Q_n stretches (n > 40). Among the possible amine donors, the glycolytic enzyme glyceraldehyde-3-phosphate-dehydrogenase was shown to tightly bind several proteins involved in polyglutamine expansion diseases. Recently, the authors have shown that K191, K268, and K331, out of the 26 lysines present in glyceraldehyde-3-phosphate-dehydrogenase, are the reactive amine-donor sites forming cross-links with substance P, which bears the simplest Q_n domain (n = 2). The present study reports that synthetic peptides of both pathological and nonpathological length (n = 43 and 17, respectively) form cross-links with the same K residues located in the C-terminal region of glyceraldehyde-3-phosphate-dehydrogenase. In addition, it is shown that extra K residues present in the C termini of glyceraldehyde-3-phosphate-dehydrogenase are susceptible to cross-linking in the presence of transglutaminase. The present results indicate a possible modulating effect of Q_n stretches on tissue transglutaminase substrate specificity and mechanism of recognition.

Keywords: Glyceraldehyde 3-phosphate dehydrogenase; lysine residues; mass spectrometry; Q_n disease; transglutaminase

Abbreviations: Asp-N, endoproteinase Asp-N • CD, circular dichroism • ESIMS, electrospray mass spectrometry • GAPDH, glyceraldehyde 3-phosphate dehydrogenase • GEE, glycine ethylester • HD, Huntington’s disease • HFIP, 1,1,1,3,3,3-hexafluoro-2-propanol • Q, glutamine residue • K, lysine residue • LC/MS, liquid chromatography mass spectrometry • MALDI/MS, matrix assisted laser desorption ionization mass spectrometry • MDC, monodansylcadaverine • Q_n, polyglutamine repeat containing n Q residues • Q₁₇, peptide with sequence RPRPRQ₁₇RPRPR • Q₁₇*, peptide with sequence Q₁₇RPRPR • Q₄₃, peptide with sequence RPRPRQ₄₃RPRPR • Q₃₈*, peptide with sequence Q₃₈RPRPR • RP-HPLC, reverse phase high pressure liquid chromatography • TFA, trifluoroacetic acid • TIC, Total Ion Current • TG, transglutaminase • tTG, guinea pig liver tissue transglutaminase • Tris, Tris(hydroxymethyl)aminomethane

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?