Biomaterial Database

Locusta-AKH-III and related peptides containing two tryptophan residues have unusual CD spectra. 1996

M J Lee, and A F Drake, and G J Goldsworthy

Department of Biology, Birkbeck College, University of London, England.

Locusta adipokinetic hormone-III (AKH-III, < QLNFTPWWa) and three analogues have been studied by CD spectroscopy. The AKH peptides examined in which the tryptophan residues are adjacent present a distinctive negative-positive CD signature, in aqueous solution, that increases at low temperatures in ethanediol/water. In the presence of 0.6% SDS, a positive-minus CD is observed. The separation of the two tryptophan residues by an aliphatic amino acid results in a CD, in aqueous solution inverted from negative to positive CD at approximately 225nm. For the peptides with two adjacent tryptophan residues, the bisignate nature of this tryptophan-based CD at lower temperatures or in SDS indicates that the indole/indole orientation can adopt two limiting conformations. There is a correlation between the size of the negative CD at 225 nm and the AKH peptide potency which may indicate a preferred indole/indole orientation by the receptor.

UI	MeSH Term	Description	Entries
D007301	Insect Hormones	Hormones secreted by insects. They influence their growth and development. Also synthetic substances that act like insect hormones.	Insect Hormone,Hormone, Insect,Hormones, Insect
D008823	Micelles	Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.	Micelle
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
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
D006110	Grasshoppers	Plant-eating orthopterans having hindlegs adapted for jumping. There are two main families: Acrididae and Romaleidae. Some of the more common genera are: Melanoplus, the most common grasshopper; Conocephalus, the eastern meadow grasshopper; and Pterophylla, the true katydid.	Acrididae,Locusts,Romaleidae,Grasshopper,Locust
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
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012967	Sodium Dodecyl Sulfate	An anionic surfactant, usually a mixture of sodium alkyl sulfates, mainly the lauryl; lowers surface tension of aqueous solutions; used as fat emulsifier, wetting agent, detergent in cosmetics, pharmaceuticals and toothpastes; also as research tool in protein biochemistry.	Sodium Lauryl Sulfate,Irium,Dodecyl Sulfate, Sodium,Lauryl Sulfate, Sodium,Sulfate, Sodium Dodecyl,Sulfate, Sodium Lauryl
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures
D014364	Tryptophan	An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.	Ardeydorm,Ardeytropin,L-Tryptophan,L-Tryptophan-ratiopharm,Levotryptophan,Lyphan,Naturruhe,Optimax,PMS-Tryptophan,Trofan,Tryptacin,Tryptan,Tryptophan Metabolism Alterations,ratio-Tryptophan,L Tryptophan,L Tryptophan ratiopharm,PMS Tryptophan,ratio Tryptophan