ROS-GC subfamily membrane guanylate cyclase-linked transduction systems: taste, pineal gland and hippocampus

In the continuous efforts to test the validity of the theme that the Ca²⁺-modulated ROS-GC subfamily system is a universal transduction component of the sensory and sensory-linked network of neurons, this article focuses on the presence and variant biochemical forms of this transduction system in the gustatory epithelium, the site of gustatory transduction; in the pineal, a light-sensitive gland; and in the hippocampus neurons, linked with the perception of all SENSES.     

A Balanced Ratio of Proteins from Gene G and Frameshift-Extended Gene GT Is Required for Phage Lambda Tail Assembly

In bacteriophage λ, the overlapping open reading frames G and T are expressed by a programmed translational frameshift similar to that of the gag-pol genes of many retroviruses to produce the proteins gpG and gpGT. An analogous frameshift is widely conserved among other dsDNA tailed phages in their corresponding “G” and “GT” tail genes even in the absence of detectable sequence homology. The longer protein gpGT is known to be essential for tail assembly, but the requirement for the shorter gpG remained unclear because mutations in gene G affect both proteins. A plasmid system that can direct the efficient synthesis of tails was created and used to show that gpG and gpGT are both essential for correct tail assembly. Phage complementation assays under conditions where levels of plasmid-expressed gpG or gpGT could be altered independently revealed that the correct molar ratio of these two related proteins, normally determined by the efficiency of the frameshift, is also crucial for efficient assembly of functional tails. Finally, the physical connection between the G and T domains of gpGT, a consequence of the frameshift mechanism of protein expression, appears to be important for efficient tail assembly.     

Biological activity of a polar lipid of Clostridium butyricum spores

A fraction of polar lipids was isolated from spores of the anaerobic bacterium Clostridium butyricum 35/11 exerting a noticeable radioprotective effect. The main biological activity of spore extracts was associated with this fraction. The fraction of polar lipids inhibited autolysis of the bacterial cell walls. The fraction was found to contain a phenolic glycolipid and a peptide component. The bacteriostatic and radiotherapeutic properties of the fraction are presumed to be due to its membranotropic activity.     

Partial protein domains: evolutionary insights and bioinformatics challenges

Protein domains are generally thought to correspond to units of evolution. New research raises questions about how such domains are defined with bioinformatics tools and sheds light on how evolution has enabled partial domains to be viable.With the rapid expansion in the number of determined protein sequences - over 92 million in UniProt in March 2015 - an ever-increasing number of biologists are using bioinformatics tools for annotation of these sequences. One widely used strategy is to identify occurrences of Pfam families within the sequence of interest [1]. A Pfam family is a multiple sequence alignment of the occurrences of a particular domain both in different species and in different regions of the same protein. The concept underpinning Pfam is that proteins typically comprise one or more domains (regions), each of which is an evolutionary unit that generally has a well-defined biological function. A significant sequence similarity between a query protein and a Pfam family provides the basis for annotations. Two recent articles [2,3] in Genome Biology evaluate the implications of having the query sequence only matching part of a Pfam family, which is an intriguing finding, given that a Pfam family is considered to be an evolutionary unit.