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Polyglutamylation as a Posttranslational Tubulin Modification
Bašta, Miroslav ; Bařinka, Cyril (advisor) ; Dráber, Pavel (referee)
α-tubulin is an essential protein for every eukaryotic cell. Together with β-tubulin, it polymerises into microtubules and participates thus in creating and maintaining cellular structures and presents a cell-wide interaction platform for a plethora of microtubule associating proteins. Primary sequences of the disordered C-termini of both α- and β-tubulin are the least conserved among tubulin isotypes and their variability is further increased by the presence of various post-translational modifications. The genetically coded, tyrosinated C-terminus of α-tubulin can be either shortened by one, two or three amino acids resulting in detyrosinated, Δ2, or Δ3 variants, respectively or it can be extended by the addition of polyglutamate or polyglycine chains. The tubulin tyrosine ligase-like (TTLL) protein family consists of 14 enzymes that participate in tubulin glutamylation, glycylation, and tyrosination. The glutamylases have two distinct activities, initiation and elongation of the polyglutamate chain. Initiases link the first glutamate residue to the γ-carboxyl group of one of the glutamates of tubulin C-termini to create a fork in the amino acid sequence. Elongases then recognise the branching glutamate and build up the polyglutamate sidechain one residue at the time. TTLL11 is an elongase of...
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Evolution of the genetic code and classification of oxymonads
Šrámová, Eliška ; Hampl, Vladimír (advisor) ; Čepička, Ivan (referee)
Oxymonads are a group of heterotrophic flagellates living in low oxygen environment. These protists inhabit mainly the gut of xylophagous insects (cockroaches, termites), with an exception of the genus Monocercomonoides, which was described from the intestinal contents of many vertebrates. On the basis of molecular data, Oxymonadida are classified into the supergroup Excavata (Cavalier-Smith, 2002; Simpson et al., 2006, Hampl et al. 2009). This thesis was focused on the diversity of genus Monocecomonoides from the morphologically simplest family Polymastigidae. The main goal of our work was to gather sequence data from strains isolated from a wide spectrum of hosts. We have obtained 26 partial sequences of the gene for the SSU rDNA in total, of which two belonged to another oxymonad, apparently genus Oxymonas. Our phylogenetic analysis indicated that the representatives of the genus Monocercomonoides form one group, however with a low bootstrap support. On the basis of published data about the presence of non-canonical genetic code in some oxymonads (Keeling and Leander, 2003; de Koning et al., 2008), we decided to explore this rare phenomenon in representatives of the genus Monocercomonoides. For this part of the study we gathered 9 partial sequences of α-tubulin gene. In these sequences we have not...
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Evolution of the genetic code and classification of oxymonads
Šrámová, Eliška ; Hampl, Vladimír (advisor) ; Čepička, Ivan (referee)
Oxymonads are a group of heterotrophic flagellates living in low oxygen environment. These protists inhabit mainly the gut of xylophagous insects (cockroaches, termites), with an exception of the genus Monocercomonoides, which was described from the intestinal contents of many vertebrates. On the basis of molecular data, Oxymonadida are classified into the supergroup Excavata (Cavalier-Smith, 2002; Simpson et al., 2006, Hampl et al. 2009). This thesis was focused on the diversity of genus Monocecomonoides from the morphologically simplest family Polymastigidae. The main goal of our work was to gather sequence data from strains isolated from a wide spectrum of hosts. We have obtained 26 partial sequences of the gene for the SSU rDNA in total, of which two belonged to another oxymonad, apparently genus Oxymonas. Our phylogenetic analysis indicated that the representatives of the genus Monocercomonoides form one group, however with a low bootstrap support. On the basis of published data about the presence of non-canonical genetic code in some oxymonads (Keeling and Leander, 2003; de Koning et al., 2008), we decided to explore this rare phenomenon in representatives of the genus Monocercomonoides. For this part of the study we gathered 9 partial sequences of α-tubulin gene. In these sequences we have not...
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