E Merzlyak | PubMed Health

PubMed2000

Semi-synthetic Rab proteins as tools for studying intermolecular interactions.

Rab GTPases play a key role in the regulation of membrane traffic. Posttranslational geranylgeranylation is critical for their biological activity and is conferred by a Rab geranylgeranyl transferase (RabGGTase). To study the interactions between Rab proteins and RabGGTase, we used in vitro ligation methodology to generate a fluorescent semi-synthetic Rab7 protein. The obtained protein was functionally active and was used to demonstrate a micromolar affinity interaction of Rab7 with the RabGGTase in the absence of Rab escort protein (REP). This finding is consistent with an earlier proposed model according to which RabGGTase possesses two independent weak binding sites for REP and Rab proteins.

Alkyl and Aryl Transferases↗

PubMedDate not supplied

Diversity and phylogeny of insect trypanosomatids based on small subunit rRNA genes: polyphyly of Leptomonas and Blastocrithidia.

With the aim of further investigating phylogenetic relationships in insect trypanosomatids, we have determined the sequences of small subunit rRNA genes from ten isolates, which were originally classified as Leptomonas, Blastocrithidia, and Wallaceina based on their morphology in the hosts. The inferred maximum likelihood, parsimony, and distance trees indicate that the Leptomonas and Blastocrithidia are polyphyletic, and confirm the polyphyly of Herpetomonas and Crithidia. Blastocrithidia triatoma and Leptomonas collosoma were among the earliest branching lineages among the insect trypanosomatids, while most other isolates were found within a closely related terminal clade, which also included Crithidia fasciculata. This analysis has clearly demonstrated that the morphological classification system of insect trypanosomatids does not always reflect their genetic affinities warranting its revision in the future.

Animals↗