α‐, β‐, and γ‐tubulins: Sequence comparisons and structural constraints

Burns, Roy G.

doi:10.1002/cm.970200302

Cited by 85 publications

(30 citation statements)

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“…Early sequence comparisons for tubulin gave valuable insights into the function of α and β-tubulin (Little, 1981;Little and Seehaus, 1988;Burns, 1991;Burns and Surridge, 1994). Alignments between the orthologs and paralogs of α and β-tubulin are unambiguous due to the highly conserved amino acid sequences between these two proteins.…”

Section: A B Cmentioning

confidence: 99%

The evolution of the structure of tubulin and its potential consequences for the role and function of microtubules in cells and embryos

et al. 2006

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This paper discusses the results of homology modeling and resulting calculation of key structural and physical properties for close to 300 tubulin sequences, including α α α α α, β β β β β, γ γ γ γ γ, δ δ δ δ δ and ε ε ε ε ε -tubulins. The basis for our calculations was the structure of the tubulin dimer In addition to the general structural trends between tubulin isoforms, we have observed that the carboxy-termini of α α α α α and β β β β β-tubulin exists in at least two stable configurations, either projecting away from the tubulin (or microtubule) surface, or collapsed onto the surface. In the latter case, the carboxy-termini form a lattice distinctly different from that of the well-known A and B lattices formed by the tubulin subunits. However, this C-terminal lattice is indistinguishable from the lattice formed when the microtubule-associated protein tau binds to the microtubule surface. Finally, we have discussed how tubulin sequence diversity arose in evolution giving rise to its particular phylogeny and how it may be used in cell-and tissue-specific expression including embryonal development.

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Section: A B Cmentioning

confidence: 99%

The evolution of the structure of tubulin and its potential consequences for the role and function of microtubules in cells and embryos

et al. 2006

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“…FtsZ3 is encoded by a lethal allele (4), deficient in GTP binding (28), and unable to form filaments. In contrast, FtsZ2, which is capable of binding GTP but deficient in GTP hydrolysis (8), is able to polymerize. Interestingly the ftsZ2 allele can support cell growth but results in a complex phenotype including cell filamentation, minicell formation, resistance to cell division inhibitors minCD and suLA, and temperature-dependent cell lysis (4).…”

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confidence: 99%

Guanine nucleotide-dependent assembly of FtsZ into filaments

1994

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FtsZ is an essential cell division protein that is localized to the leading edge of the bacterial septum in a cytokinetic ring. It contains the tubulin signature motif and is a GTP binding protein with a GTPase activity.Further comparison of FtsZ with eukaryotic tubulins revealed some additional sequence similarities, perhaps indicating a similar GTP binding site. Examination of FtsZ incubated in vitro by electron microscopy revealed a guanine nucleotide-dependent assembly into protein filaments, supporting the hypothesis that the FtsZ ring is formed through self-assembly. FtsZ3, which is unable to bind GTP, does not polymerize, whereas FtsZ2, which binds GTP but is deficient in GTP hydrolysis, is capable of polymerization.FtsZ is an essential cell division protein in Escherichia coli (11,31,37) and Bacillus subtilis (2) and is conserved in other eubacteria (10). In both E. coli and B. subtilis FtsZ is localized in a ring at the division site (5, 39). In E. coli, certain mutant FtsZs lead to an altered ring geometry and abnormal polar morphology, suggesting that FtsZ determines septal morphogenesis (6). The FtsZ ring is formed at midcell before there is visible invagination, is located at the leading edge of the septum throughout division, and is dispersed upon completion of division. One possible explanation for the dynamic behavior of FtsZ is that it undergoes a reversible polymerization reaction (24). Interestingly, FtsZ contains a glycine-rich sequence motif (GGGTGTG) that is important for GTP binding (13,28,32). A similar sequence, (A/G)GGTG(S/A)G, is present in eukaryotic tubulins and has been designated the tubulin signature motif (42). In addition, FtsZ has a GTPase activity that shows a dependence upon the protein concentration, suggesting that the GTPase activity is dependent upon protein oligomerization (13,28,39). Therefore, we have examined the effect of GTP upon FtsZ oligomerization.E. coli FtsZ isolated from an overproducing strain migrates as a single species in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) but yields multiple species upon native gel electrophoresis ( Fig. 1) (12). The median molecular weight of these species obtained from size exclusion chromatography is 500,000, equivalent to approximately 12 monomers (28). This result indicates that FtsZ self-associates, which has also been inferred from the genetics of ftsZ (4,40).To determine if the oligomerization state of FtsZ is affected by GTP, purified FtsZ was incubated with GTP at 37°C and examined by freeze-etch electron microscopy (20). Examination of FtsZ incubated in the absence of GTP revealed the presence of particles that were larger (diameters ranging from 5 to 15 nm; Fig. 2A) than expected for FtsZ monomers (4 to 6 nm, assuming a spherical shape) but consistent with the range of sizes estimated from size exclusion chromatography. In contrast, examination of FtsZ after incubation with GTP revealed the presence of numerous fibers of variable length with a calculated diameter of 7 nm (Fig. 2B) Initial atte...

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“…The extremely homologous regions included the diagnostic portion from aa 401 to 409, which is conserved exclusively within the -tubulin subclass. 20) Fig. 2.…”

Section: Analysis Of and Tubulin Sequencesmentioning

confidence: 99%