Single stranded binding protein: Difference between revisions
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==Other SSB Structures== | ==Other SSB Structures== | ||
<StructureSection load='2vw9' size='400' side='left' frame='true' caption='Structure of Single Stranded DNA-Binding Protein from ''Helicobacter pylori' 'bound to ssDNA (PDB entry [[2vw9]])' scene=''> Though the SSB of E. coli is perhaps the best characterized, ssDNA binding proteins of many other organisms have also been identified. Some proteins, such as the SSB of E. coli and human mitochondrial SSBs, bind as tetramers to ssDNA. However, the SSB can have from one to as many as four OB-fold containing subunits in its structure. For example, the structure of the SSB from Helicobacter pylori shown to the left is a homodimer composed of two identical subunits, each with the an OB-fold motif made of similar secondary structure elements such as an α-helix and several β-sheets. Just like in the E. coli SSB, the OB-fold area in each subunit is used for single-stranded nucleic acid binding. A phenylalanine residue (PHE56) is again integral to ssDNA binding, as it is a site of cross-linking. Tryptophan and lysine residues again play an important role in binding of ssDNA to the protein. | <StructureSection load='2vw9' size='400' side='left' frame='true' caption='Structure of Single Stranded DNA-Binding Protein from ''Helicobacter pylori' 'bound to ssDNA (PDB entry [[2vw9]])' scene=''> | ||
Though the SSB of E. coli is perhaps the best characterized, ssDNA binding proteins of many other organisms have also been identified. Some proteins, such as the SSB of E. coli and human mitochondrial SSBs, bind as tetramers to ssDNA. However, the SSB can have from one to as many as four OB-fold containing subunits in its structure. For example, the structure of the SSB from Helicobacter pylori shown to the left is a homodimer composed of two identical subunits, each with the an OB-fold motif made of similar secondary structure elements such as an α-helix and several β-sheets. Just like in the E. coli SSB, the OB-fold area in each subunit is used for single-stranded nucleic acid binding. A phenylalanine residue (PHE56) is again integral to ssDNA binding, as it is a site of cross-linking. Tryptophan and lysine residues again play an important role in binding of ssDNA to the protein. | |||
As single-stranded DNA binding proteins are utilized in some of the most important aspects of DNA metabolism, they are used extensively in DNA replication, repair and recombination. Most SSBs use one or more subunits with an OB-fold motif to bind securely and preferentially to ssDNA. A few specific SSBs (such as RecA and adenovirus DBP) do not use the OB-fold, instead relying on electrostatic and stacking interactions as well as hydrogen bonding. | As single-stranded DNA binding proteins are utilized in some of the most important aspects of DNA metabolism, they are used extensively in DNA replication, repair and recombination. Most SSBs use one or more subunits with an OB-fold motif to bind securely and preferentially to ssDNA. A few specific SSBs (such as RecA and adenovirus DBP) do not use the OB-fold, instead relying on electrostatic and stacking interactions as well as hydrogen bonding. | ||