Fourier transform infrared spectroscopy of sup 13 C double bond O-labeled phospholipids hydrogen bonding to carbonyl groups

Journal Article · Tue Oct 18 00:00:00 EDT 1988 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00421a038· OSTI ID:6896416

Blume, A; Huebner, W; Messner, G ^[1]

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1. Institut fuer Physikalische Chemie, Freiburg (West Germany)

Fourier transform infrared spectroscopy has been used to characterize the carbonyl stretching vibration of DMPC, DMPE, DMPG, and DMPA, all labeled with {sup 13}C at the carbonyl group of the sn-2 chain. Due to the vibrational isotope effect, the {sup 13}C{double bond}O and the {sup 12}C{double bond}O vibrational bands are separated by ca. 40-43 cm{sup {minus}1}. This frequency difference does not change when the labeling is reversed with the {sup 13}C{double bond}O group at the sn-1 chain. For lipids in organic solvents possible conformational differences between the sn-1 and sn-2 ester groups have no effect on the vibrational frequency of the C{double bond}O groups. In aqueous dispersion unlabeled phospholipds always show a superposition of two bands for the C{double bond}O vibration located at ca. 1,740 and 1,727 cm{sup {minus}1}. FT-IR spectra of {sup 13}C-labeled phospholipids show that the vibrational bands of both are clearly superpositions of at least two underlying components of different frequency and intensity. Band frequencies were determined by Fourier self-deconvolution and second-derivative spectroscopy. To extract quantitative information about changes in hydration, band profiles were simulated with Gaussian-Lorentzian functions. The chemical nature of the head group and its electronic charge have distinctive effects on the extent of hydration of the carbonyl groups. In the gel and liquid-crystalline phase of DMPC the sn-2 C{double bond}O group is more hydrated than the sn-1 C{double bond}O. This is accord with the conformation determined by X-ray analysis. In DMPG the sn-1 C{double bond}O group seems to be more accessible to water, indicating a different conformation of the glycerol backbone.

• OSTI ID: 6896416
• Journal Information: Biochemistry; (USA), Vol. 27:21; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARBON 13
CHEMICAL BONDS
OXYGEN
PHOSPHOLIPIDS
PHASE STUDIES
ABSORPTION SPECTROSCOPY
FOURIER TRANSFORMATION
HEAVY WATER
INFRARED SPECTRA
LABELLED COMPOUNDS
VIBRATIONAL STATES
CARBON ISOTOPES
ELEMENTS
ENERGY LEVELS
ESTERS
EVEN-ODD NUCLEI
EXCITED STATES
HYDROGEN COMPOUNDS
INTEGRAL TRANSFORMATIONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
NONMETALS
NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
SPECTRA
SPECTROSCOPY
STABLE ISOTOPES
TRANSFORMATIONS
WATER
550601* - Medicine- Unsealed Radionuclides in Diagnostics