Accession Number : AD0659947

Title :   INFRARED SPECTRA OF SURFACE FILMS OF POLY-GAMMA-METHYL-L-GLUTAMATE.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Loeb,George ; Baier,Robert E.

Report Date : 20 JUL 1967

Pagination or Media Count : 16

Abstract : Surface pressure vs area isotherms of poly-gamma-methyl-L-glutamate spread on water from solutions of chloroform differed from those obtained when the polymer was spread from solutions of high pyridine concentration. Samples for studying infrared spectra of the material forming the monolayer were obtained by collapsing the monolayer onto a transparent plate or by depositing a monolayer by the Blodgett technique onto a multiple internal reflection prism. When solutions of the polypeptide were spread from chloroform upon water in a Langmuir-Adam film balance to form an insoluble monolayer, a plateau in the force-area isotherm and a large limiting area were observed. Spectra of these monolayers were characterized by amide I and II regions characteristic of the alpha-helical or random configuration. There was not a change in secondary structure corresponding to the plateau region detectable via the IR spectra. Spreading solutions of high pyridine concentration led to isotherms without a plateau and with a much smaller limiting area. Spectra of these monolayers showed a significant amount of beta-type material. This is the first unambiguous correlation between the infrared spectra of uncollapsed monolayers of polypeptides and their behavior at the air/water interface. (Author)

Descriptors :   (*PEPTIDES, *MONOMOLECULAR FILMS), GLUTAMIC ACID, POLYMERS, INFRARED SPECTRA, STEREOCHEMISTRY, INTERFACES, PYRIDINES, MOLECULAR ROTATION, SURFACES

Subject Categories : Biochemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE