鏈菌鹼

Ki: 18 μM (Bacterial RNA polymerase)
Kd: 15 μM (Bacterial RNA polymerase)

The antibiotic Streptolydigin (Stl) is a derivative of 3-acetyltetramic acid. Binding of Streptolydigin to RNA polymerase strictly depends on a noncatalytic magnesium ion which is likely chelated by the aspartate of the bridge helix of the active center.
Streptolydigin inhibits T. thermophilus RNA polymerase with a K _i of 1.8 μM.
Streptolydigin (Stl) inhibits initiation, elongation, and pyrophosphorolysis by bacterial RNA polymerase. Streptolydigin interacts with three structural elements within RNAP: the Stl pocket, the bridge helix, and the trigger-loop region. The Streptolydigin streptolol moiety interacts with the Streptolydigin pocket and bridge helix, and the Streptolydigin tetramic-acid moiety interacts with the trigger-loop region.