Large-Scale Candidate Gene Analysis of HDL Particle Features

Background: HDL cholesterol (HDL-C) is an established marker of cardiovascular risk with significant genetic determination. However, HDL particles are not homogenous, and refined HDL phenotyping may improve insight into regulation of HDL metabolism. We therefore assessed HDL particles by NMR spectroscopy and conducted a large-scale candidate gene association analysis. Methodology/Principal Findings: We measured plasma HDL-C and determined mean HDL particle size and particle number by NMR spectroscopy in 2024 individuals from 512 British Caucasian families. Genotypes were 49,094 SNPs in >2,100 cardiometabolic candidate genes/loci as represented on the HumanCVD BeadChip version 2. False discovery rates (FDR) were calculated to account for multiple testing. Analyses on classical HDL-C revealed significant associations (FDR<0.05) only for CETP (cholesteryl ester transfer protein; lead SNP rs3764261: p = 5.6*10(-15)) and SGCD (sarcoglycan delta; rs6877118: p = 8.6*10(-6)). In contrast, analysis with HDL mean particle size yielded additional associations in LIPC (hepatic lipase; rs261332: p = 6.1*10(-9)), PLTP (phospholipid transfer protein, rs4810479: p = 1.7*10(-8)) and FBLN5 (fibulin-5; rs2246416: p = 6.2*10(-6)). The associations of SGCD and Fibulin-5 with HDL particle size could not be replicated in PROCARDIS (n = 3,078) and/or the Women's Genome Health Study (n = 23,170). Conclusions: We show that refined HDL phenotyping by NMR spectroscopy can detect known genes of HDL metabolism better than analyses on HDL-C

High pressure crystallographic structures of Ras give insight on high-energy states involved in interactions with regulators

CERVOXY COLLNational audienc

High pressure crystallographic structures of Ras give insight on high-energy states involved in interactions with regulators

CERVOXY COLLNational audienc

High pressure 31P NMR spectroscopy on guanine nucleotides

The P-31 NMR pressure response of guanine nucleotides bound to proteins has been studied in the past for characterizing the pressure perturbation of conformational equilibria. The pressure response of the P-31 NMR chemical shifts of the phosphate groups of GMP, GDP, and GTP as well as the commonly used GTP analogs GppNHp, GppCH(2)p and GTP gamma S was measured in the absence and presence of Mg2+-ions within a pressure range up to 200 MPa. The pressure dependence of chemical shifts is clearly non-linear. For all nucleotides a negative first order pressure coefficient B (1) was determined indicating an upfield shift of the resonances with pressure. With exception of the alpha-phosphate group of Mg2+center dot GMP and Mg2+center dot GppNHp the second order pressure coefficients are positive. To describe the data of Mg2+center dot GppCH(2)p and GTP gamma S a Taylor expansion of 3rd order is required. For distinguishing pH effects from pressure effects a complete pH titration set is presented for GMP, as well as GDP and GTP in absence and presence of Mg2+ ions using indirect referencing to DSS under identical experimental conditions. By a comparison between high pressure P-31 NMR data on free Mg2+-GDP and Mg2+-GDP in complex with the proto-oncogene Ras we demonstrate that pressure induced changes in chemical shift are clearly different between both forms

Influence of decreasing solvent polarity (1,4-dioxane/water mixtures) on the stability and structure of complexes formed by copper(II), 2,2`-bipyridine or 1,10-phenanthroline and guanosine 5`-diphosphate : evaluation of isomeric equilibria

The stability constants of the 1 : 1 complexes formed between Cu(Arm)2+, where Arm = 2,2`-bipyridine or 1,10-phenanthroline, and guanosine 5`-diphosphate (GDP)3- or its monoprotonated form H(GDP)2- were determined by potentiometric pH titrations in water and in water containing 30 or 50 stability of the binary Cu(GDP)- complex is enhanced due to macrochelate formation of the diphosphate-coordinated Cu2+ with N7 of the guanine residue as previously shown. In Cu(Arm)(GDP)- the N7 is released from Cu2+ and the stability enhancement of more than one log unit in aqueous solution is clearly attributable to intramolecular stack formation between the aromatic rings of Arm and the guanine moiety. Indeed, stacked isomers occur to more than 90 with open unstacked forms. Surprisingly, the same formation degrees of the stacks are observed for Cu(Arm)(dGMP) complexes, where dGMP2- = 2`-deoxyguanosine 5`-monophosphate, despite the fact that the overall stability of the latter species is by about 2.7 log units lower. In 1,4-dioxane-water mixtures stack formation is drastically reduced, probably due to hydrophobic solvation of the aromatic rings by the ethylene bridges of 1,4-dioxane. The relevance of these results regarding biological systems is indicated