Abstract
The x-ray structure of the deoxy oligonucleotide dodecamer d(CGCGTTAACGCG) recently determined in our laboratory shows that the helical parameters of the central TTAA segment are significantly different compared to the central AATT in d(CGCGAATTCGCG). The roll in the central TA step of the T2A2 dodecamer opens towards the minor groove while the AT step of the A2T2 dodecamer opens towards the major groove. Also, the roll angles at the steps 4 and 8 (GT and AC in T2A2) and (GA and TC in A2T2) are in opposite directions. The high cup and helical twist angles at the central base-pair of T2A2 decreases the base stacking interactions compared to A2T2. Tilt angles within the tetranucleotide segments TTAA and AATT have opposite signs. In spite of the local differences caused by the sequence inversion (TTAA----AATT), the two dodecamers exhibit similar overall bending. The top third is more bent than the bottom third relative to the central segment. This asymmetric bending in the two dodecamers is mainly due to crystal packing interactions.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
