Structural and Experimental Evidence for the Enantiomeric Recognition toward a Bulky sec-Alcohol by Candida antarctica Lipase B

Abstract

Candida antarctica lipase B (CAL-B) exhibits remarkable enantioselectivity for various chiral sec-alcohols, and the enantioselectivity is structurally well-understood. Two substituents at the chiral center of a sec-alcohol separately bind two pockets, namely, large and medium binding pockets. It has been believed that the medium pocket is too small to accommodate a large substituent (larger than an ethyl group), and thus, bulky secalcohols bearing two large substituents have been regarded as a poor substrate for CAL-B. However, we found that CAL-B can catalyze the transesterification of N-Boc-protected rac-2-amino-1-phenylethanol (1a) enantioselectively with a moderate reaction rate. X-ray crystallography and computer modeling revealed that the rotation of the Leu278 side chain creates a space to accept the N-Boc-aminomethylene group of 1a. Moreover, a sec-alcohol substrate with less than one hydrogen atom at the γ-position from the hydroxyl group is required to achieve a moderate reaction rate. On the basis of this observation, we diversified bulky N-Boc-protected rac-2-amino-1-arylethanols for the transesterifications with high enantioselectivities (E > 200).

Perspectives on the Role of Enzymatic Biocatalysis for the Degradation of Plastic PET

“…The binding pocket is divided into two compartments with different affinities—one that accommodates the acyl moiety and the other that preferably binds the substrate alcohol part [ 188 , 189 , 192 ]. The alcohol-binding subsite is further divided into a large and a medium pocket [ 193 ].…”

Asymmetric Synthesis of Stereogenic Phosphorus P(V) Centers Using Chiral Nucleophilic Catalysis

“…These compounds normally have stable configurations depending on the nature of the substitution around the phosphorus center [9]. Chiral phosphate mimics have been extensively utilized in transition metal catalysts, [10] as chiral reagents, [11][12][13] and in coordination chemistry [14,15]. Furthermore, compounds with stereogenic phosphonate centers are of great interest in biological applications [16].…”

Efficient production of wild-type lipase B from Candida antarctica in the cytoplasm of Escherichia coli

“…Sixteen crystal structures exist for CalB in the protein data bank [2,[26][27][28][29][30][31] with the protein either purified from the natural source or recombinant expression in P. pastoris, A. oryzae, A. niger or E. coli.…”