[Bioinformatic search for plant homologs of protein kinase BUB1--the keypoint of mitotic spindle assembly].

Fourteen plant homologs of animal, yeast and myxomycetes spindle assembly checkpoint protein kinases were identified bioinformatically. It was shown that the closest plant homologues of the BUB1 protein kinases are unknown proteins XP_002274770.1 (CBI21878.1) from Vitis vinifera, EEC82122.1 from Oryza sativa Indica, EEE67244.1 from O. sativa Japonica, EEF44403.1 from Ricinus communis and CAL57156.1 from Ostreococcus tauri. The reconstruction and analysis of spatial structures of the EEC82122.1, EEE67244.1 and XP_002274770.1 (CBI21878.1), catalytic domains confirmed their conformity to spindle assembly checkpoint protein kinases BUB1.

[Cytochrome P-450 distribution in endoplasmic reticulum membranes of rat liver]. / Izuchenie raspredeleniia tsitokhroma P-450 v membranakh endoplazmaticheskogo retikuluma pecheni krysy.

Using electron-dense labelling in combination with solubilization, the localization of cytochrome P-450 in the microsomal membranes was studied. It was shown that cytochrome P-450 is unevenly distributed in the membrane and has 2-3 reactive SH-groups. The molecules of solubilized cytochrome P-450 contain 4-5 reactive SH-groups and show a tendency to aggregate. A comparative study of cytochrome P-450 distribution in the microsomal ghosts membranes in proteoliposomes was carried out.

[Modification of phospholipid liposomes by electron dense labels]. / Modifikatsii fosfolipidnykh liposom élektronno-plotnymi metkami.

Phosphatidilethanolamine (PE) of liposome was modified by electron-density label, trichlortriazin being used as an intermediate reagent. The electron microscopic study of pure PE liposomes has revealed the presence of typical lamellar structure which also has been visualized on PE liposomes modified by electron-density label. In case of liposomes which consist of PE and phosphatidilcholine cluster distribution of modified PE molecules was observed.

[Study of the topography of the nitrogenase active center by the electron microscopy method with the use of the electron density labels]. / Izuchenie topografii aktivnogo tsentra nitrogenazy metodom elektronnoi mikroskopii s primeneniem elektronoplotnykh metok.

The electron microscopy method has been used for studying the topography of the active centre of the nitrogenase in combination with the method of electron density labels. The active centre has been shown to place on the nitrogenase macromolecule asymmetrically. The non-heme iron atoms of the nitrogenase active centre have been regularly packed and located on the macromolecule as a quadrangular cluster closely to the surface of subunits. Two free sulfhydryl groups of the ATP-site of the nitrogenase active centre are in close proximity to the cluster. ATP-site of the nitrogenase active centre containing these groups is located on the Fe-enzyme, while the main part of the iron-containing cluster is located on the Mo-Fe-enzyme.