The Relationship of Precursor Cluster Concentration in a Saturated Crystallization Solution to Long-Range Order During the Transition to the Solid Phase.

A model for the transition from disordered liquid state to the solid phase has been proposed based on establishing a correlation between the concentration of precursor clusters in a saturated solution and the features of solid phase formation. The validity of the model has been verified experimentally by simultaneously studying the oligomeric structure of lysozyme protein solutions and the peculiarities of solid phase formation from these solutions. It was shown that no solid phase is formed in the absence of precursor clusters (octamers) in solution; perfect monocrystals are formed at a small concentration of octamers; mass crystallization is observed with an increasing degree of supersaturation (and concentration of octamers); further increase in octamer concentration leads to the formation of an amorphous phase.

HRas and Myc synergistically induce cell cycle progression and apoptosis of murine cardiomyocytes.

Aim: Adult mammalian cardiomyocytes are incapable of significant proliferation, limiting regeneration after myocardial injury. Overexpression of the transcription factor Myc has been shown to drive proliferation in the adult mouse heart, but only when combined with Cyclin T1. As constitutive HRas activity has been shown to stabilise Cyclin T1 , we aimed to establish whether Myc and HRas could also act cooperatively to induce proliferation in adult mammalian cardiomyocytes .

The binding of precipitant ions in the tetragonal crystals of hen egg white lysozyme.

The bonds between lysozyme molecules and precipitant ions in single crystals grown with chlorides of several metals are analysed on the basis of crystal structure data. Crystals of tetragonal hen egg lysozyme (HEWL) were grown with chlorides of several alkali and transition metals (LiCl, NaCl, KCl, NiCl and CuCl) as precipitants and the three-dimensional structures were determined at 1.35 Å resolution by X-ray diffraction method.

Dodecamers derived from the crystal structure were found in the pre-crystallization solution of the transaminase from the thermophilic bacterium by small-angle X-ray scattering.

The pre-crystallization solution of the transaminase from (TaTT) has been studied by small-angle X-ray scattering (SAXS). Regular changes in the oligomeric composition of the protein were observed after the addition of the precipitant. Comparison of the observed oligomers with the crystal structure of TaTT (PDB ID 6GKR) shows that dodecamers may act as building blocks in the growth of transaminase single crystals.

Pre-crystallization phase formation of thermolysin hexamers in solution close to crystallization conditions.

Communicated by Ramaswamy H. Sarma.