5A71

Open and closed conformations and protonation states of Candida antarctica Lipase B: atomic resolution native

Summary for 5A71

• Entry DOI: 10.2210/pdb5a71/pdb
• Related: 5A6V
• Descriptor: LIPASE B, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ISOPROPYL ALCOHOL, ... (6 entities in total)
• Functional Keywords: hydrolase, lipase, candida antarctica, atomic resolution, free fatty acids, lipids, hydrolase fold, interfacial activation
• Biological source: PSEUDOZYMA ANTARCTICA
• Total number of polymer chains: 2
• Total formula weight: 67380.90

Authors

Stauch, B.,Fisher, S.J.,Cianci, M. (deposition date: 2015-07-02, release date: 2015-10-21, Last modification date: 2024-10-16)

Primary citation

Stauch, B.,Fisher, S.J.,Cianci, M.
Open and Closed States of Candida Antarctica Lipase B: Protonation and the Mechanism of Interfacial Activation.
J.Lipid Res., 56:2348-, 2015

PubMed Abstract: Lipases (EC 3.1.1.3) are ubiquitous hydrolases for the carboxyl ester bond of water-insoluble substrates, such as triacylglycerols, phospholipids, and other insoluble substrates, acting in aqueous as well as in low-water media, thus being of considerable physiological significance with high interest also for their industrial applications. The hydrolysis reaction follows a two-step mechanism, or "interfacial activation," with adsorption of the enzyme to a heterogeneous interface and subsequent enhancement of the lipolytic activity. Among lipases, Candida antarctica lipase B (CALB) has never shown any significant interfacial activation, and a closed conformation of CALB has never been reported, leading to the conclusion that its behavior was due to the absence of a lid regulating the access to the active site. The lid open and closed conformations and their protonation states are observed in the crystal structure of CALB at 0.91 Å resolution. Having the open and closed states at atomic resolution allows relating protonation to the conformation, indicating the role of Asp145 and Lys290 in the conformation alteration. The findings explain the lack of interfacial activation of CALB and offer new elements to elucidate this mechanism, with the consequent implications for the catalytic properties and classification of lipases.

PubMed: 26447231
DOI: 10.1194/JLR.M063388

Experimental method

X-RAY DIFFRACTION (0.91 Å)