Amino-acid sequence data of beta-tubulin from Physarum polycephalum myxamoebae
| Autor: | Monika Singhofer-Wowra, Lesley Clayton, Keith Gull, Peter J. Dawson, Melvyn Little |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Centriole
Physarum polycephalum macromolecular substances Biochemistry Fungal Proteins Physarum Tubulin Microtubule Endopeptidases Trypsin Amino Acid Sequence Cyanogen Bromide Mitosis Peptide sequence Chromatography High Pressure Liquid biology Hydrolysis Serine Endopeptidases fungi biology.organism_classification Molecular biology Spindle apparatus biology.protein |
| DOI: | 10.1111/j.1432-1033.1986.tb10492.x |
| Popis: | Starting with 7.7 mg of a p-tubulin isolated from myxamoebae of the slime mould Physarum polycephalum, 90% of the sequence has been determined by the Edman degradation of peptides generated by cyanogen bromide, trypsin and Staphylococcus aureus protease. Differences to other P-tubulins are mainly conservative and spread evenly throughout the chain except for a high concentration at the C-terminus. The Physarum P-tubulin shows most homology to Chlamydomonas B-tubulin (90.5%) and least homology to yeast j-tubulin (S. cerevisiae, 73.4%). Two tryptic peptides were isolated in approximately equal quantities which were identical except in one position (S/ALTVPELTQRMFDA) showing that at least two j-tubulins are present in myxamoebae. However, since this was the only heterogeneity found, these P-tubulins are probably very similar. The tubulin polypeptides of Physarum polycephalum myxamoebae function in centrioles, cytoplasmic microtubules and mitotic spindle microtubules. Myxamoebae can undergo two dinstinct transformations to produce two further celltypes: the flagellate and the plasmodium. These transformations are accompanied by precise rearrangements of microtubules and expression of other tubulin polypeptides. The differentiation of myxamoebae into flagellates takes place rapidly when cells are placed into water and involves the acquisition of two flagella and the rearrangement of cytoplasmic microtubules. Flagellates are incapable of division and must return to the myxamoebal form in order to continue growth and proliferation. Myxamoebae can transform into plasmodia by mating or selfing dependent upon the strain; the resulting plasmodium is a large multinucleated cell which does not possess cytoplasmic microtubules. Thus, although tubulin polypeptides are present in the plasmodium throughout the cell cycle they are only polymerized during mitosis when they form the microtubules of the intranuclear spindle. Studies of the Physarum genome using restriction fragment length polymorphisms have clearly revealed the presence of multiple tubulin DNA loci [l]. In addition, it is now apparent from a number of studies [2-41 that the Physarum plasmodium and myxamoebae express different tubulin isotypes. Myxamoebae appear to express four tubulin isotypes: al, a2, pl and p2. These isotypes are defined on the basis of their coordinates on two-dimensional polyacrylamide gels. There is evidence that at least some of these gel electromorphs are complex and may contain the products of different tubulin genes [4, 51. Thus, the different cell types of Physarum contain different microtubule organelles and show a selective expression of tubulin isotypes. The extent of the differences between isotypes is not known, nor is it clear whether a particular tubulin polypeptide is required for a specific function. We have therefore investigated the structure of several Physarum tubulins. We recently reported the nucleotide sequence of an a-tubulin expressed in the plasmodia] form [6]. In this paper we describe the amino acid sequence of the j?-tubulin isolated from the unicellular myxamoebal form of Physarum. |
| Databáze: | OpenAIRE |
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