Biomaterial Database

Structure of the 50S ribosomal subunit from Escherichia coli. Investigation of the intact subunit and core particles by electron microscopy and analogue image processing. 1979

E Spiess

Structures of 50S ribosomal subunits, CsCl and ethidium bromide core particles from these subunits have been investigated by electron microscopy and image processing by FAIRS. This method revealed structural details which are obscured in individual images, and enabled to distinguish six crown forms, different in their side protuberances, and two kidney forms. Crown forms were imaged as symmetrical or asymmetrical forms. The latter type was far more frequent in untreated populations than the first. The depletion of proteins by both agents caused stepwise degradation of the side protuberances in the crown forms thereby transforming asymmetrical to symmetrical forms. It is concluded from these findings that asymmetrical and symmetrical forms in untreated populations represent also structurally different particles. From the higher complexity in terms of component composition and structure it is concluded that the asymmetrical crown forms are more likely to represent the native structure of isolated 50S subunits than the symmetrical forms. Existing models for this subunit are discussed in terms of this finding.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D004996	Ethidium	A trypanocidal agent and possible antiviral agent that is widely used in experimental cell biology and biochemistry. Ethidium has several experimentally useful properties including binding to nucleic acids, noncompetitive inhibition of nicotinic acetylcholine receptors, and fluorescence among others. It is most commonly used as the bromide.	Ethidium Bromide,Homidium Bromide,Novidium,Bromide, Ethidium,Bromide, Homidium
D012269	Ribosomal Proteins	Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.	Proteins, Ribosomal,Ribosomal Protein,Protein, Ribosomal
D012270	Ribosomes	Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.	Ribosome
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships