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The Structures and Properties of Poly‐5‐methylcytidylic Acid
Author(s) -
Warshaw Myron M.,
Noe Ralph
Publication year - 1972
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1972.360110611
Subject(s) - ionic strength , chemistry , optical rotatory dispersion , titration , polymer , dispersion (optics) , ionic bonding , helix (gastropod) , melting temperature , triple helix , polymer chemistry , crystallography , analytical chemistry (journal) , stereochemistry , ion , circular dichroism , aqueous solution , organic chemistry , materials science , optics , composite material , ecology , physics , snail , biology
The optical rotatory dispersion properties of poly 5MeC, poly diMeC, and 5MeCMP‐(5′) in 0.1 M Na+ have been studied at various pH values and temperatures. Poly 5MeC and poly diMeC have optical properties which are similar to those for poly C; however, poly 5MeC has a biphasic melting profile in the pH range from 3.8 to 5.4 similar to that observed for poly 51C. Using titration, ionic strength, and pH dependence measuements, the data for poly 5MeC are interpreted in terms of the following scheme at pH 4.0 and 0.1 ionic strength: triple‐strand helix 37°C double‐strand helix 79°C single‐strand coil. Support for this scheme is discussed. The effect of the methyl group is discussed in terms of similar structural possibilities for other polymers of cytidylic acid.