chlamydocin Chlamydocin is a cyclic tetrapeptide. Chlamydocin is a very potent inhibitor of cell proliferation. Chlamydocin was shown to be a very potent histone deacetylase (DDAC) inhibitor with an IC50 value of 1.3 nM. Some data also indicate a potential link between degradtation of survivin and activation of the apoptotic pathway induced by HDAC inhibitors.