This is a Src homology-3 (SH3) like beta-barrel domain which can be found in Dda enzyme. Dda is a phage T4 SF1B helicase. The Dda SH3 domain contains two insertions (compared to RecD2), a second beta-ribbon that is referred to as the hook and a beta- ...
This is a Src homology-3 (SH3) like beta-barrel domain which can be found in Dda enzyme. Dda is a phage T4 SF1B helicase. The Dda SH3 domain contains two insertions (compared to RecD2), a second beta-ribbon that is referred to as the hook and a beta-ribbon/two-helix substructure that is referred to as the tower. The tower region within the domain is rigidly connected to domain 2A in Dda and appears to be specifically designed for the task of supporting the extended pin. Hence, it is suggested that 2A and this SH3 domain move as one unit during the ATP-driven translocation of ssDNA while maintaining contact with the pin. In this scenario, the pin-tower interaction can be considered as an additional transmission site that serves to more efficiently couple the energy from ATP binding and hydrolysis to the unwinding of dsDNA [1].