Structure of rabbit muscle aldolase at low resolution.
J Biol Chem
; 260(28): 15286-90, 1985 Dec 05.
Article
em En
| MEDLINE
| ID: mdl-4066671
ABSTRACT
X-ray diffraction data were measured by x-ray diffractometry to 5-A resolution for both the monoclinic form of rabbit skeletal muscle aldolase (EC 4.1.2.13) and a platinum derivative. The heavy atom difference patterson was solved at 6-A resolution yielding eight distinct heavy atom sites. Choice was made of the enantiomorph and protein phases were calculated on the basis of single isomorphous replacement differences. The electron density map calculated from these phases was averaged according to the non-crystallographic molecular symmetry. Rotational symmetry analysis of native patterson and site symmetry analysis of refined heavy atom positions are consistent with the aldolase tetramer possessing a very high degree of 222 internal symmetry. The subunits in the tetramer are positioned in a tetrahedral configuration displaying a slight square planar deformation. Each subunit is roughly ellipsoidal in shape with the major axis nearly parallel to a local 2-fold axis. Prominent at the surface of each subunit were structural features resembling alpha helices. Each subunit contributes to its boundary surface at least six helices which are arranged in a barrel-like manner and possessing a right handed twist with respect to each other. Density associated with binding of substrate on the enzyme was located on the surface of each subunit. Cooperative aspects of the conformational changes produced upon substrate binding are discussed.
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Base de dados:
MEDLINE
Assunto principal:
Frutose-Bifosfato Aldolase
/
Músculos
Limite:
Animals
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1985
Tipo de documento:
Article