ABSTRACT
Small angle x-ray scattering and viscometric analyses of the alpha-zeins of maize in solution indicated that the molecules were asymmetric. Structure predictions of consensus sequences for the two classes of alpha-zeins, Z19 and Z22, were in good agreement with the alpha-helical contents determined by circular dichroism. Dimensions determined by small angle x-ray scattering and viscometry indicated a predominantly alpha-helical conformation. The data are discussed in relation to models for the solution conformation and to earlier models for alpha-zeins structure.
Subject(s)
Zea mays/chemistry , Zein/chemistry , Amino Acid Sequence , Circular Dichroism , Molecular Sequence Data , Protein Conformation , Scattering, Radiation , SolutionsABSTRACT
A method for the direct screening of bacterial lambda libraries by polymerase chain reaction technology has been developed. This technique permits the identification and isolation of specific DNA sequences without the need for any filter hybridisation or radioactive probing. This strategy has been used to isolate a gene encoding lactate dehydrogenase from a Lactococcus lactis lambda library.
Subject(s)
Gene Library , Genes, Bacterial , Polymerase Chain Reaction/methods , Amino Acid Sequence , Animals , Bacteria/genetics , Bacteriophage lambda/genetics , Cloning, Molecular , Conserved Sequence , Humans , L-Lactate Dehydrogenase/genetics , Lactococcus lactis/enzymology , Lactococcus lactis/genetics , Molecular Sequence Data , Sequence Homology, Amino Acid , Species SpecificityABSTRACT
Small angle X-ray scattering was used to study the solution conformation of the C hordeins of barley (Hordeum vulgare), a group of proteins whose primary structure consists predominantly of an octapeptide repeat motif. Measurements on the protein in 0.1 M-acetic acid at 25 degrees C are consistent with a model for the protein conformation of a stiff coil, the so-called 'worm-like' chain. The characteristic parameters (the Kuhn statistical segment length and the contour length) of the protein were calculated as 5.11 and 71.5 nm respectively.
Subject(s)
Hordeum/chemistry , Plant Proteins/chemistry , Glutens , Protein Conformation , Scattering, Radiation , Solutions , X-RaysABSTRACT
Scanning tunneling microscopy has been used to demonstrate that a spiral structure based on beta-reverse turns is adopted by the repeat sequences present in a group of wheat gluten proteins. This structure is similar to the beta-spiral formed by a synthetic polypentapeptide based on a repeat sequence present in elastin. Wheat gluten and elastin are both elastomeric and it is possible that the spiral structure contributes to this property.
