RESUMO
IBIS is a set of computer programs dedicated to the processing of electron micrographs, mainly for structural analysis of biological macromolecules. We present IBIS version 3, a UNIX/OSF/Motif 1.2-based package which carries out and provides visual display of the many operations essential to image analysis. To ensure portability, the software is written in FORTRAN 77 for computing mathematical functions and in C for display routines. A description of the IBIS OSF/Motif interface is given with the new functions added to the original version. IBIS v.3 is available free of charge to other laboratories on the internet via anonymous ftp (URL: ftp://ftp.univ-rennes1.fr/pub/ incoming/IBIS.tar.Z).
Assuntos
Processamento de Imagem Assistida por Computador/métodos , Microscopia Eletrônica/métodos , Software , Redes de Comunicação de Computadores , Substâncias Macromoleculares , Estrutura Molecular , Linguagens de Programação , Interface Usuário-ComputadorRESUMO
'IBIS' is a set of computer programs concerned with the processing of electron micrographs, with particular emphasis on the requirements for structural analyses of biological macromolecules. The software is written in FORTRAN 77 and runs on Unix workstations. A description of the various functions and the implementation mode is given. Some examples illustrate the user interface.
Assuntos
Processamento de Imagem Assistida por Computador , Microscopia Eletrônica , Software , Sistemas Computacionais , Análise de Fourier , Linguagens de Programação , Design de Software , Interface Usuário-ComputadorRESUMO
Human alpha 2-macroglobulin is a tetrameric plasma inhibitor of proteinases. Its dissociation by Cd2+ gives functional dimers. Electron microscopy of negatively stained dimers shows their round-ended cylindrical shape with furrows delimiting 3 main stain-excluding domains. Image processing of electron micrographs shows the existence of 2 main orientations of the dimers on the carbon support film. The dimer is composed of 2 curved monomers linked in a central domain, and related by a 90 degree rotation. Taking into account the known primary structure of alpha 2-macroglobulin and the linkage of the 2 constitutive monomers by 2 disulfide bonds, the molecular organization of the dimer is discussed, extended to the tetrameric molecule and compared to the published models of human alpha 2-macroglobulin.
