An Overview of DNA-Protein Interactions

DNA Protein interactions play very vital roles in any living cell. It controls various cellular processes which are very essential for living beings, viz. replication, transcription, recombination, DNA repair etc. There are several types of proteins found in a cell. But only those proteins interact with DNA, which have the DNA binding domains. Each DNA binding domain has at least one motif, which is a conserved amino acid sequence of this protein, which can potentially recognize a double stranded or a single stranded DNA. These DNA binding domains possess an affinity to bind to either double stranded or single stranded DNA. There are mainly two broad types of DNA protein interactions: 1) Sequence specific DNA binding and 2) Sequence non-specific DNA binding. In case of sequence specific DNA protein interactions, a DNA binding protein binds to a DNA on a site having a specific nucleotide sequence. But in case of sequence non specific DNA protein interactions, the DNA binding protein can bind to a DNA in a random position on the DNA. As for example, the sequence specific DNA protein interaction is found to occur in case of transcription. The transcription factors are a special kind of DNA binding proteins. They can only recognize a specific DNA sequence. The sequence non-specific DNA protein interaction occurs in replication. During replication the DNA double strand is melted by helicase enzyme, and a replication fork is made. A special kind of protein called single strand binding protein or SSB binds to the melted single strand of DNA and stabilizes the system by preventing them to be re-natured. There are several motifs present, which are involved in DNA binding, for example, helix-turn-helix, leucine zipper, zinc finger, helix-loop-helix etc. In this review, comprehensive analyses of DNA-protein interactions are made. The detailed discussions on the topic would be very much essential for all fields of biochemistry and biophysics. Keywords: DNA-protein binding, Specificity of binding, Non-specific interaction, DNA binding motifs, Domains, DNA.