Conformational study of insect adipokinetic hormones using NMR constrained molecular dynamics

Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH₂), Tem-HrTH (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH₂) and Del-CC (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-Gly-Asn-NH₂) are adipokinetic hormones, isolated from the corpora cardiaca of different insect species. These hormones regulate energy metabolism during flight and so are intimately involved in an insect's mobility. Secondary structural elements of these peptides and the N7 analogue, [N7]-Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asn-Trp-NH₂), have been determined in dimethylsulfoxide solution using NMR restrained molecular mechanic simulations. The neuropeptides were all found to have an extended structure for the first 4 residues and a -turn between residues 4–8. For Tem-HrTH and Del-CC, asparagine (N7) which is postulated to be involved in receptor binding and/or activation, projects outward form the -turn. Mem-CC does not have an asparagine at position 7 while, for [N7]-Mem-CC, the N7 sidechain folds inside the -turn preventing its interaction with the receptor.     

Quantitative detection of dye labelled DNA using surface enhanced resonance Raman scattering (SERRS) from silver nanoparticles

The detection of dye labelled DNA by surface enhanced resonance Raman scattering (SERRS) is reported. The dye labels used are commercially available and have not previously been used as SERRS dyes. Detection limits using two excitation frequencies were determined for each label. This expands the range of labels which can be used for surface enhanced resonance Raman scattering with silver nanoparticles.     

Products of independent,normally attracted random variables

Summary LetR _n denote the correlation coefficient of ann-sample of pairs (X _i ,Y _i ), each distributed as (X, Y). AssumeX andY are independent and in the domain of attraction of the Normal law. It is shown that this entailsXY being in that domain of attraction, and thatd _n R _n N(0, 1) in distribution for constantsd _n satisfying lim sup(n ^1/2/d _n )1. Examples illustrate details of these limit theorems.     

Bounds for arrays of dots with distinct slopes or lengths

Ann×m sonar sequence is a subset of then×m grid with exactly one point in each column, such that the vectors determined by them are all distinct. We show that for fixedn the maximalm for which a sonar sequence exists satisfiesn–Cn ^11/20<m<n+4n ^2/3 for alln andm>n+c logn log logn for infinitely manyn.Another problem concerns the maximal numberD of points that can be selected from then×m grid so that all the vectors have slopes. We proven ^1/2Dn ^4/5 Supported by Hungarian National Foundation for Scientific Research, Grant No. 1901Research conducted by Herbert Taylor was sponsored in part by the Office of Naval Research under ONR Contract No. N00014-90-J-1341.