Biomaterial Database

A structural model for maize zein proteins. 1982

P Argos, and K Pedersen, and M D Marks, and B A Larkins

With the knowledge of the amino acid sequences of two maize zein proteins (apparent molecular weights of 19,000 and 22,000), a structural model is proposed for their molecular conformation. The circular dichroic spectrum taken in the 190-240 nm range for a zein protein mixture in methanol solution showed the zein secondary structure to be largely helical. The polar, hydrophobic, and turn characteristics of the zein residues, as well as the homologous repeat units in their primary sequences, suggested a structure with nine adjacent, topologically antiparallel helices clustered within a distorted cylinder. Polar residues distributed along the helical surfaces allowed intra- and intermolecular hydrogen bonding such that the zein molecules could be arranged in planes. The proposed glutamine-rich turns located between the helices and at the cylindrical caps would favor side chain interactions resulting in stacking of the molecular planes. Physical properties observed for the zein proteins are explained by the model.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D003313	Zea mays	A plant species of the family POACEAE. It is a tall grass grown for its EDIBLE GRAIN, corn, used as food and animal FODDER.	Corn,Indian Corn,Maize,Teosinte,Zea,Corn, Indian
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D015028	Zein	A group of alcohol-soluble seed storage proteins from the endosperm of corn.
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular