ChemInform Abstract: AQUEOUS SOLUTION CONFORMATION OF RIGID NUCLEOSIDES AND NUCLEOTIDES

1976 ◽  
Vol 7 (35) ◽  
pp. no-no
Author(s):  
CHE-HUNG LEE ◽  
RAMASWAMY H. SARMA
Keyword(s):  
Aqueous Solution ◽  
Solution Conformation

Aqueous solution conformation of rigid nucleosides and nucleotides

1976 ◽  
Vol 98 (12) ◽  
pp. 3541-3548 ◽  
Author(s):  
Che-Hung Lee ◽  
Ramaswamy H. Sarma
Keyword(s):  
Aqueous Solution ◽  
Solution Conformation

scholarly journals A spectroscopic study of the mitochondrial transit peptide of rat malate dehydrogenase

1994 ◽  
Vol 303 (2) ◽  
pp. 657-662 ◽  
Author(s):  
L K MacLachlan ◽  
P I Haris ◽  
D G Reid ◽  
J White ◽  
D Chapman ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Malate Dehydrogenase ◽  
Structural Characteristics ◽  
Transit Peptide ◽  
Helical Structure ◽  
Terminal Sequence ◽  
Solution Conformation ◽  
Helical Content ◽  
Ft Ir ◽  
Nuclear Overhauser

A peptide corresponding to the N-terminal sequence of the rat malate dehydrogenase, comprising the transit sequence and two residues of the mature protein (MLSALARPVGAALR-RSFSTSAQNNAK) has been chemically synthesized, and its structural characteristics investigated by Fourier-transform i.r. (FT-IR), c.d. and 1H-n.m.r. spectroscopy. FT-IR and c.d. spectra of the peptide were recorded in a variety of environments (aqueous solution, trifluoroethanol) and after incorporation into phospholipid bilayers. The peptide was found to be mainly in aperiodic or undefined conformation in aqueous solution. However, in trifluoroethanol a marked increase in alpha-helical content was observed. An increase in alpha-helical content was also observed in negatively charged lipids (dimyristoylphosphatidylglycerol and cardiolipin). However, when reconstituted in a zwitterionic phospholipid (dimyristoylphosphatidylcholine), no alpha-helical structure was observed. N.m.r. spectroscopy was used to characterize the helical structure in greater detail in trifluoroethanol. The 1H-n.m.r. spectrum of the peptide in this solvent was assigned using standard homonuclear two-dimensional methods. The observed patterns of nuclear Overhauser enhancements confirmed the deductions obtained from c.d. and FT-1R spectroscopy concerning the solution conformation, suggesting a region of flexible nascent helix between Ala-4 and Ser-18. This structure is discussed in terms of the possible function of the peptide.

Vibrational Raman optical activity of alanyl peptide oligomers: A new perspective on aqueous solution conformation

Biopolymers ◽  
1994 ◽  
Vol 34 (3) ◽  
pp. 303-313 ◽  
Author(s):  
Steven J. Ford ◽  
Zai Q. Wen ◽  
Lutz Hecht ◽  
Laurence D. Barron
Keyword(s):  
Aqueous Solution ◽  
Optical Activity ◽  
Solution Conformation ◽  
Raman Optical Activity ◽  
New Perspective

Characterization of Methylprednisolone Esters of Hyaluronan in Aqueous Solution:  Conformation and Aggregation Behavior

2005 ◽  
Vol 6 (3) ◽  
pp. 1648-1653 ◽  
Author(s):  
Anna Taglienti ◽  
Massimiliano Valentini ◽  
Paolo Sequi ◽  
Vittorio Crescenzi
Keyword(s):  
Aqueous Solution ◽  
Aggregation Behavior ◽  
Solution Conformation

scholarly journals Hyaluronan: the absence of amide–carboxylate hydrogen bonds and the chain conformation in aqueous solution are incompatible with stable secondary and tertiary structure models

2006 ◽  
Vol 396 (3) ◽  
pp. 487-498 ◽  
Author(s):  
Charles D. Blundell ◽  
Paul L. Deangelis ◽  
Andrew Almond
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Tertiary Structure ◽  
Amide Proton ◽  
Solution Conformation ◽  
Tertiary Structures ◽  
Nmr Data ◽  
Carboxylate Groups ◽  
Correlation Spectrum ◽  
Secondary And Tertiary Structure

Contradictory descriptions for the aqueous solution conformation of the glycosaminoglycan hyaluronan (HA) exist in the literature. According to hydrodynamic and simulation data, HA molecules are stiffened by a rapidly interchanging network of transient hydrogen bonds at the local level and do not significantly associate at the global level. In marked contrast, models derived from NMR data suggest that the secondary structure involves persistent hydrogen bonds and that strong associations between chains can occur to form vast stable tertiary structures. These models require an extended 2-fold helical conformation of the HA chain and specific hydrogen bonds between amide and carboxylate groups. To test these descriptions, we have used 15N-labelled oligosaccharides and high-field NMR to measure pertinent properties of the acetamido group. The amide proton chemical shift perturbation and carboxylate group pKa value are inconsistent with a highly populated hydrogen bond between the amide and carboxylate groups. Amide proton temperature coefficients and chemical exchange rates confirm this conclusion. Comparison of oligomer properties with polymeric HA indicates that there is no discernible difference in amide proton environment between the centre of octasaccharides and the polymer, inconsistent with the formation of tertiary structures. A [1H-1H-15N] NOESY-HSQC (heteronuclear single-quantum correlation) spectrum recorded on an HA octasaccharide revealed that amide groups in the centre are in a trans orientation and that the average solution conformation is not an extended 2-fold helix. Therefore the two key aspects of the secondary and tertiary structure models are unlikely to be correct. Rather, these new NMR data agree with descriptions from hydrodynamic and simulations data.

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