Detection of polyunsaturated omega-6 fatty acid in human malignant prostate tissue by 1D and 2D high-resolution magic angle spinning NMR spectroscopy.

Object: Polyunsaturated omega-6 fatty acids (PUFAs) have been shown to promote prostate cancer. Here, we describe the use of HRMAS NMR spectroscopy to detect omega-6 PUFA species in prostate tissues.

Materials And Methods: Samples originating from non-malignant (n = 54) and malignant (n = 27) prostate tissues (from 27 prostatectomized men) were studied by 1D (1)H, 2D (1)H-(1)H and (1)H-(13)C HRMAS NMR spectroscopy followed by histopathological characterization.

1H and 13C NMR investigation of the influence of nonligated residue contacts on the heme electronic structure in cyanometmyoglobin complexes reconstituted with centro- and pseudocentrosymmetric hemins.

The 1H and 13C chemical shifts for the heme methyls of low-spin, ferric sperm whale cyanometmyoglobin reconstituted with a variety of centrosymmetric and pseudocentrosymmetric hemins have been recorded and analyzed to shed light on the nature of heme-protein contacts, other than that of the axial His, that modulate the rhombic perturbation to the heme's in-plane electronic asymmetry. The very similar 1H dipolar shifts for heme pocket residues in all complexes yield essentially the same magnetic axes as in wild type, and the resultant dipolar shifts allow the direct determination of the heme methyl proton and 13C contact shifts in all complexes. It is demonstrated that, even when the magnetic axes and anisotropies are known, the intrinsic uncertainties in the orientational parameters lead to a sufficiently large uncertainty in dipolar shift that the methyl proton contact shifts are inherently significantly less reliable indicators of the unpaired electron spin distribution than the methyl 13C contact shifts.

Dissociation and unfolding of cold-active alkaline phosphatase from atlantic cod in the presence of guanidinium chloride.

Cold-adaptation of enzymes involves improvements in catalytic efficiency. This paper describes studies on the conformational stability of a cold-active alkaline phosphatase (AP) from Atlantic cod, with the aim of understanding more clearly its structural stability in terms of subunit dissociation and unfolding of monomers. AP is a homodimeric enzyme that is only active in the dimeric state.

Heat-labile bacterial alkaline phosphatase from a marine Vibrio sp.

Psychrophilic organisms have successfully adapted to various low-temperature environments such as cold ocean waters. Catalysts with increased catalytic efficiencies are produced, generally at the expense of thermal stability due to fewer non-covalent stabilizing interactions. A marine bacterial strain producing a particularly heat-labile alkaline phosphatase was selected from a total of 232 strains isolated from North-Atlantic coastal waters.

Cryo-TEM and NMR studies of a micelle-forming phosphoglucolipid from membranes of Acholeplasma laidlawii A and B.

The chemical structure of a phosphoglucolipid from the membrane of the bacterium Acholeplasma laidlawii strain B-PG9 has been determined by high resolution NMR to be 1,2-diacyl-3-O-[glycerophosphoryl-6-O-(alpha-D-glucopyranosyl-(1 -->2)-O-alpha-D-glucopyranosyl)]-sn-glycerol (GPDGlcDAG). It was concluded that this lipid has exactly the same structure as one of the phosphoglucolipids from A. laidlawii strain A-EF22.

Two-dimensional 1H-NMR of transmembrane peptides from Escherichia coli phosphatidylglycerophosphate synthase in micelles.

Two 28-residue peptides, PTLLTLFRVILIPFFVLVFYKKKGKKKG [Pgs-(6-25)-peptidyl-KKKGKKKG; Pgs peptide A] and VEYAGIALFFVAAVLTLWSMLQYLSAAR [Pgs-(149-176)-peptide, Pgs peptide E], were synthesized and studied by CD and two-dimensional 1H-NMR spectroscopy. The first 20 amino acid residues of Pgs peptide A are identical to one predicted transmembrane segment (Pro6-Tyr25) of the integral membrane protein phosphatidylglycerophosphate synthase (Pgs) of Escherichia coli. Pgs peptide E is identical to another predicted transmembrane segment (Val149-Arg176), which is located in the C-terminal end of this lipid synthase.

Structure of digalactosyldiacylglycerol from oats.

Digalactosyldiacylglycerol (DGalDAG) is one of the major lipids in the cells of higher plants. DGalDAG forms a lamellar liquid crystalline phase together with water. Lipid aggregates can thus be prepared which are of potential interest for use within the cosmetic and pharmaceutical industries.

Structures of glucolipids from the membrane of Acholeplasma laidlawii strain A-EF22. III. Monoglucosyldiacylglycerol, diglucosyldiacylglycerol, and monoacyldiglucosyldiacylglycerol.

The structures of three glucolipids from the membrane of Acholeplasma laidlawii, strain A-EF22, were determined by high resolution 1H-NMR and 13C-NMR spectroscopy. The two most abundant glucolipids in this organism were shown to be 1,2-diacyl-3-O-(alpha-D-glucopyranosyl)-sn-glycerol (MGlcDAG) and 1,2-diacyl-3-O-[alpha-D-glucopyranosyl-(1 --> 2)-O-alpha-D- glucopyranosyl]-sn-glycerol (DGlcDAG). These structures agree with those determined previously by chemical analyses of the two most abundant glucolipids synthesized by the B strain of A.

Structures of glucolipids from the membrane of Acholeplasma laidlawii strain A-EF22. II. Monoacylmonoglucosyldiacylglycerol.

The structure of one glucolipid from the membrane of Acholeplasma laidlawii, strain A-EF22, was determined. This glucolipid is synthesized only when a large fraction of saturated, straight-chain fatty acids are incorporated into the membrane lipids of strain A-EF22. The lipid was studied by 1H- and 13C-NMR spectroscopy.

Structures of glucolipids from the membrane of Acholeplasma laidlawii strain A-EF22. I. Glycerophosphoryldiglucosyldiacylglycerol and monoacylbisglycerophosphoryldiglucosyldiacylglycerol.

The structures of two phosphoglucolipids from the membrane of Acholeplasma laidlawii, strain A-EF22 were determined by high resolution 13C-, 31P- and 1H-NMR. The lipids in question are 1,2-diacyl-3-O-[glycerophosphoryl-6-O-(alpha-D-glucopyranosyl- (1-->2)-O-alpha-D-glucopyranosyl)]-sn-glycerol (1) and 1,2-diacyl-3-O-[glycerophosphoryl-6-O-(alpha-D-glucopyranosyl-(1-- >2)- monoacyl-glycerophosphoryl-6-O-alpha-D-glucopyranosyl)]-sn-glycero l (2). Both lipids are thus derivatives of diglucosyldiacylglycerol.

Regulation and phase equilibria of membrane lipids from Bacillus megaterium and Acholeplasma laidlawii strain A containing methyl-branched acyl chains.

Phosphatidylethanolamine (PE) was isolated from Bacillus megaterium grown at 20 and 55 degrees C (PE-20 and PE-55). Iso and anteiso methyl-branched, saturated acyl chains are predominant in B. megaterium, and the value of the molar ratio of iso/anteiso acyl chains is more than 20-fold higher in PE-55 than in PE-20.

Membrane lipid regulation in Acholeplasma laidlawii grown with saturated fatty acids. Biosynthesis of a triacylglucolipid forming reversed micelles.

The membrane lipid composition in several strains of Acholeplasma laidlawii is regulated upon a change in the growth conditions. Monoglucosyldiacylglycerol (MGlcDAG) and diglucosyldiacylglycerol (DGlcDAG) are the most abundant lipids in the A. laidlawii membrane.

Effect of head-group structure and counterion condensation on phase equilibria in anionic phospholipid-water systems studied by 2H, 23Na, and 31P NMR and X-ray diffraction.

The phase equilibria, hydration, and sodium counterion association for the systems DOPA-2H2O, DOPS-2H2O, DOPG-2H2O, and DPG-2H2O were investigated with 2H, 23Na, and 31P NMR and X-ray diffraction. The following one-phase regions were found in the DOPA-water system: a reversed hexagonal liquid-crystalline (HII) phase up to about 35 wt % water and a lamellar liquid-crystalline (L alpha) phase between about 55 and 98 wt % water. The area per DOPA molecule was 36-65 A2 in the HII phase (10-40 wt % water) and 69 A2 in the L alpha phase (60 wt % water).

1H-NMR study of the mechanism of assembly and equilibrium heme orientation of sperm whale myoglobin reconstituted with protohemin type-isomers.

The products of the incorporation of various protohemin type-isomers into the heme pocket of sperm whale myoglobin were investigated by 1H-NMR in the met-cyano complexes, both immediately after reconstitution as well as at equilibrium. The type-isomers studied include those involving all possible interchanges of the two substituents on a given pyrrole. The protohemin-III and -XIII isomers, with true 2-fold symmetry, yielded only homogeneous products.