The original online version of this article (Kitadokoro, K., Matsui, S., Osokoshi, R., Nakata, K. and Kamitani, S. (2018) Expression, Purification and Crystallization of Thermostable Mutant of Cutinase Est1 from Thermobifida alba. Advances in Bioscience and Biotechnology, 9, 215-223. https://doi.org/10.4236/abb.2018.95015) unfortunately contains some mistakes. The author wishes to correct the errors.

2.1. Protein Expression and Purification

Est1(A68V/T253P) was used throughout this study (Table 1) [6]. Briefly, 20 mL of an overnight culture of E.coli cells Rosetta-gami B (DE3) transformed with pQE80L-est1(A68V/T253P) was inoculated to 400 mL of LB medium with 50 µg∙ml⁻¹ ampicillin.

Determination of Specific Activity

Enzymatic activities were determined by using p-nitrophenylbutyrate (pNPB) ester substrates as previously described [6]. The reaction was performed at 310 K in 1 mL of the mixture containing 50 mM Tris-HCl buffer (pH 8.0), 1 mM pNPB and 0.001 mM enzyme. The reaction mixture without the enzyme was used as the control. Reactions were started by the addition of pNPB.

Acknowledgements

We are grateful to all members of beamline BL44XU at SPring-8 for their help in collecting data. Use of the synchrotron beamline BL44XU at SPring-8 was obtained through the Cooperative Research Program of the Institute for Protein Research, Osaka University.