Confers DNA tethering and processivity to DNA polymerases and other proteins. Acts as a clamp, forming a ring around DNA (a reaction catalyzed by the clamp-loading complex) which diffuses in an ATP-independent manner freely and bidirectionally along dsDNA. Initially characterized for its ability to contact the catalytic subunit of DNA polymerase III (Pol III), a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria; Pol III exhibits 3'-5' exonuclease proofreading activity. The beta chain is required for initiation of replication as well as for processivity of DNA replication. Binds ds- and ssDNA. Binds the antibiotic griselimycin and its derivatives with high affinity (1.0 x 10(-10) to 2.0 x 10(-10) M sec(-1)). Binding occurs in a hydrophobic cleft between domains 2 and 3, which have been shown to be responsible for binding DNA polymerases and other DNA-modifying proteins