The circular dichroism of poly d(AAT): d(ATT) and poly r(AAU):r(AUU). A test of the first-neighbor hypothesis

✍ Scribed by Donald M. Gray; Robert L. Ratliff; D. Lloyd Williams

• Publisher: Wiley (John Wiley & Sons)
• Year: 1973
• Tongue: English
• Weight: 792 KB
• Volume: 12
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1973.360120604

✦ Synopsis

Abstract

We present absorption and circular dichroism (CD) spectra for the synthetic polymers poly d(AAT):d(AAT) and poly r(AAU):r(AAU), in both native and heat‐denatured forms. As a means of evaluating the first‐neighbor hypothesis, the CD spectra are compared with approximations derived from spectra of other synthetic polymers containing the same first‐neighbor sequences. This is the first instance where such a comparison has been possible using spectra of double‐stranded RNA sequences, and the agreement between the measured and approximated spectra for poly r(AAU):r(AUU) is surprisingly good. We have also subjected the CD spectrum of poly d(AAT):d(AAT) to a previously published analytical procedure for obtaining estimates of first‐neighbor frequencies. In this first independent test of the procedure, we find that the analysis does infer the existence of a majority (86%) of AA, TT, AT, and TA first neighbors but does not precisely indicate their relative proportions.