The Vavilov Institute’s (VIR) contribution to the survey and study of Vavilovia formosa (Fabaceae)

In the 1960s–1980s, the Vavilov Institute of Plant Industry, known worldwide as VIR, organized a substantial series of studies dedicated to a Caucasian endemic, the Pliocene relic Vavilovia formosa (Fabeae: Fabaceae). Those investigations are little known to the scientific community, although, in fact, the priority right for integrated research into this plant belongs to VIR. As a result of the cycle of studies, the first ideas about the biology and ecology of the species, the manner of its reproduction, its intraspecific diversity, the degree of crossability with other members of the tribe, its karyotype and anatomy were developed. The plants of V. formosa are not reproduced ex situ and their germplasm is absent in the world’s gene banks. Therefore, collecting V. formosa plants in their hard-to-reach habitats in the mountains is always crucial for research purposes, so a number of collecting expeditions were launched to the Greater Caucasus. The data thus obtained are discussed in the context of modern achievements in world science regarding this species.

Homologous ligands accommodated by discrete conformations of a buried cavity

Conformational change in protein–ligand complexes is widely modeled, but the protein accommodation expected on binding a congeneric series of ligands has received less attention. Given their use in medicinal chemistry, there are surprisingly few substantial series of congeneric ligand complexes in the Protein Data Bank (PDB). Here we determine the structures of eight alkyl benzenes, in single-methylene increases from benzene to n-hexylbenzene, bound to an enclosed cavity in T4 lysozyme. The volume of the apo cavity suffices to accommodate benzene but, even with toluene, larger cavity conformations become observable in the electron density, and over the series two other major conformations are observed. These involve discrete changes in main-chain conformation, expanding the site; few continuous changes in the site are observed. In most structures, two discrete protein conformations are observed simultaneously, and energetic considerations suggest that these conformations are low in energy relative to the ground state. An analysis of 121 lysozyme cavity structures in the PDB finds that these three conformations dominate the previously determined structures, largely modeled in a single conformation. An investigation of the few congeneric series in the PDB suggests that discrete changes are common adaptations to a series of growing ligands. The discrete, but relatively few, conformational states observed here, and their energetic accessibility, may have implications for anticipating protein conformational change in ligand design.

The Pottery from the Sites on Plumpton Plain

A substantial series of pottery was submitted to me from both the Plumpton Plain sites. Its examination has emphasized the distinction of date between them. It will appear that Site A belongs to the earlier part of the Late Bronze Age, from perhaps about 1000 B.C., whereas Site B cannot be dated before about 750 B.C., and covers the transition to the Early Iron Age in the period approximately centred on 500 B.C.