2

TREND: a platform for exploring protein function in prokaryotes based on phylogenetic, domain architecture and gene neighborhood analyses

Key steps in a computational study of protein function involve analysis of (i) relationships between homologous proteins, (ii) protein domain architecture and (iii) gene neighborhoods the corresponding proteins are encoded in. Each of these steps …

How bacterial chemoreceptors evolve novel ligand specificities

Chemoreceptor-based signaling pathways are among the major modes of bacterial signal transduction, and Pseudomonas aeruginosa PAO1 is an important model to study their function. Of the 26 chemoreceptors of this strain, PctA has a broad ligand range …

MiST 3.0: an updated microbial signal transduction database with an emphasis on chemosensory systems

https://mistdb.com

Trimeric structure of the ligand-binding domain suggests a mode of communication in bacterial chemoreceptors

Transmembrane chemoreceptors are widely present in Bacteria and Archaea. They play a critical role in sensing various signals outside and transmitting to the cell interior. Here, we report the structure of the periplasmic ligand-binding domain (LBD) of the transmembrane chemoreceptor MCP2201, which governs chemotaxis to citrate and other organic compounds in Comamonas testosteroni. The apo-form LBD crystal revealed a typical four-helix bundle homodimer, similar to previously well-studied chemoreceptors such as Tar and Tsr of Escherichia coli. However, the citrate-bound LBD revealed a four-helix bundle homotrimer that had not been observed in bacterial chemoreceptor LBDs. This homotrimer was further confirmed with size-exclusion chromatography, analytical ultracentrifugation and cross-linking experiments. The physiological importance of the homotrimer for chemotaxis was demonstrated with site-directed mutations of key amino acid residues in C. testosteroni mutants.

A di-iron protein recruited as an Fe[II] and oxygen sensor for bacterial chemotaxis functions by stabilizing an iron-peroxy species

Many bacteria contain cytoplasmic chemoreceptors that lack sensor domains. Here, we demonstrate that such cytoplasmic receptors found in 8 different bacterial and archaeal phyla genetically couple to metalloproteins related to β-lactamases and nitric …

Cross talk between chemosensory pathways that modulate chemotaxis and biofilm formation

Complex chemosensory systems control multiple biological functions in bacteria, such as chemotaxis, gene regulation, and cell cycle progression. Many species contain more than one chemosensory system per genome, but little is known about their …

Characterization of squamous cell lung cancers from Appalachian Kentucky

Background: Lung cancer is the leading cause of cancer mortality in the United States (U.S.). Squamous cell carcinoma (SQCC) represents 22.6% of all lung cancers nationally, and 26.4% in Appalachian Kentucky (AppKY), where death from lung cancer is …

Comparative study of the effect of disease causing and benign mutations in position Q92 on cholesterol binding by the NPC1 N-terminal domain

The Niemann-Pick type C1 (NPC1) protein is a large transmembrane protein located in lysosomes/endosomes. NPC1 binds cholesterol (CLR) and transports it to cellular membrane and endoplasmic reticulum. Mutations in NPC1 cause Niemann-Pick type C (NPC) …

Insights into the evolution of host association through the isolation and characterization of a human periodontal pathogen, Desulfobulbus oralis

The human oral microbiota encompasses representatives of many bacterial lineages that have not yet been cultured. Here we describe the isolation and characterization of previously uncultured Desulfobulbus oralis, the first human-associated …

Phylogenetic and protein sequence analysis of bacterial chemoreceptors

Identifying chemoreceptors in sequenced bacterial genomes, revealing their domain architecture, inferring their evolutionary relationships, and comparing them to chemoreceptors of known function become important steps in genome annotation and …