Sequence-dependent collective properties of DNAs and their role in biological systems

摘要

DNA actively interacts with proteins involved in replication, transcription, repair, and regulation processes inside the cell. The base sequence encodes the dynamics of these transformations from the atomic to the nanometre scale length, and over higher spatial scales. In fact, although an important part of the DNA informational content acts locally, it exerts its functions as collective properties of relatively long sequences and manifests as static and dynamic curvature. Physical models that explore different aspects of DNA collective properties associated to such superstructural properties encoded in the sequence will be reviewed. The B-DNA periodicity operates as band-pass-filter; only the local physical-chemical variance associated to the sequence, in phase with the helical periodicity, sums up and reveals at higher scale. In this light, the gel electrophoresis behaviour of DNAs, the nucleosome thermodynamic stability and positioning along genomes were interpreted and discussed. Finally, a part of this review is reserved to describe the ability of some inorganic crystal surfaces to recognize and stabilize certain DNA tracts with peculiar sequences. The collective superstructural properties of DNAs could be involved in the selective interaction between DNA sequence and particular crystal surfaces. It may be conceived that sequences strongly adsorbed on surface could nucleate and expand bits of information in primeval DNA (and/or RNA) chains, early characterized by random sequences, since more protected against the physical-chemical injuries by the environment, and therefore involved in the evolution of their informational content.