Abstract Quadruple collaboration has risen rapidly in place of the traditional triple helix model institutional between universities, governments, and companies. Loet Leydesdorff Helen Lawton Smith (2022) approach this challenge by aiming to resolve issue evaluating analyzing various quadruple n-tuple helices. This article seeks recognize increasing complexity new developing issues helices as a...

The strategy for the survival of a biological organism is closely related to the distribution of proteins in various families. As for membrane proteins, it is believed that the members of the same family usually have the same number of transmembrane helices. For example, G-protein coupled receptors form a large superfamily, most of which have seven transmembrane helices. Therefore, the number d...

Although α−helices and ÿsheets dominate the composition of proteins, other secondary structures nd their places therein too. 310 and π-helices are two such rare secondary structures. There is very little objective insight about various statistical aspects regarding the nature of their occurrences. Comprehensive set of reasons behind the existence of 310 and π-helices can only be obtained if the...

Very short alanine peptide helices can be studied in a fixed-nucleus, helix-forming system [Siedlicka, M., Goch, G., Ejchart, A., Sticht, H. & Bierzynski, A. (1999) Proc. Natl. Acad. Sci. USA 96, 903-908]. In a 12-residue sequence taken from an EF-hand protein, the four C-terminal peptide units become helical when the peptide binds La(3+), and somewhat longer helices may be made by adding alani...

Plasmids encoding "split" lactose permease constructs with discontinuities in either the periplasmic loop between helices V and VI (N(5)/C(7)) or between helices VI and VII (N(6)/C(6)) were used to localize helix VI within the tertiary structure by site-directed thiol cross-linking. A total of 57 double-Cys pairs, with one Cys residue in helix VI and another in helix V or VIII, were studied wit...

An analysis of secondary structures (alpha-helices and beta-strands) in the two terminal regions of polypeptide chains reveals features different from those observed over the whole protein structure. Compared with the overall distribution, the helices in the N-terminal region tend to be smaller and have higher propensities to contain Gln and Leu, while the C-terminal helices are longer and have...

The prediction of transmembrane (TM) helices plays an important role in the study of membrane proteins, given the relatively small number (approximately 0.5% of the PDB) of high-resolution structures for such proteins. We used two datasets (one redundant and one non-redundant) of high-resolution structures of membrane proteins to evaluate and analyse TM helix prediction. The redundant (non-redu...

The folding and stability of transmembrane proteins is a fundamental and unsolved biological problem. Here, single bacteriorhodopsin molecules were mechanically unfolded from native purple membranes using atomic force microscopy and force spectroscopy. The energy landscape of individual transmembrane alpha helices and polypeptide loops was mapped by monitoring the pulling speed dependence of th...