1 Merck Research Laboratories, Merck & Co., Rahway, NJ 07065, USA. Electronic address: jeffrey_moore@merck.com.
2 Institute of Biochemistry, Department of Biotechnology & Enzyme Catalysis, Greifswald University, 17487 Greifswald, Germany. Electronic address: uwe.bornscheuer@uni-greifswald.de.