2154-1264 Yulia Yuzenkova Mohammad Roghanian and Nikolay Zenkin transcription Multiple active centers of multi-subunit RNA polymerases Landes Bioscience 2012-05-01 115 - 118 Transcription 3-3 Landes Bioscience The active center of multi-subunit RNA polymerase consists of two modules, the Mg²⁺ module, holding the catalytic Mg²⁺ ion, and a module made of a flexible domain, the Trigger Loop. Uniquely, the “TL module” can be substituted by “alternative modules,” thus changing the catalytic properties of the active center. http://dx.doi.org/10.4161/trns.19887 http://www.landesbioscience.com/journals/transcription/article/19887/ article Point-of-View