Solvent-induced lid opening in lipases: a molecular dynamics study.

In most lipases, a mobile lid covers the substrate binding site. In this closed structure, the lipase is assumed to be inactive. Upon activation of the lipase by contact with a hydrophobic solvent or at a hydrophobic interface, the lid opens.

The isoelectric region of proteins: a systematic analysis.

Background: Binding of proteins in ion exchange chromatography is dominated by electrostatic interactions and can be tuned by adjusting pH and ionic strength of the solvent. Therefore, the isoelectric region (IER), the pH region of almost zero charge near the pI, has been used to predict the binding properties of proteins.

Principal Findings: Usually the IER is small and binding and elution is carried out at pH values near to the pI.

Rational design of Pseudozyma antarctica lipase B yielding a general esterification catalyst.

Pseudozyma antarctica lipase B (CALB) shows activity in the acrylation of hydroxypropylcarbamate, a racemic mixture of enantiomers of primary and secondary alcohols. However, full conversion is hampered by the slowly reacting S enantiomer of the secondary alcohol. The same is true for a wide range of secondary alcohols, for example, octan-2- and -3-ol.

Modelling substrate specificity and enantioselectivity for lipases and esterases by substrate-imprinted docking.

Background: Previously, ways to adapt docking programs that were developed for modelling inhibitor-receptor interaction have been explored. Two main issues were discussed. First, when trying to model catalysis a reaction intermediate of the substrate is expected to provide more valid information than the ground state of the substrate.

Isolation and molecular characterization of a novel D-hydantoinase from Jannaschia sp. CCS1.

Hydantoinases (HYDs) are important enzymes for industrial production of optically pure amino acids, which are widely used as precursors for various semi-synthetic antibiotics. By a process coupling genomic data mining with activity screening, a new hydantoinase, tentatively designated HYD(Js), was identified from Jannaschia sp. CCS1 and overexpressed in Escherichia coli.

Modeling of solvent-dependent conformational transitions in Burkholderia cepacia lipase.

Background: The characteristic of most lipases is the interfacial activation at a lipid interface or in non-polar solvents. Interfacial activation is linked to a large conformational change of a lid, from a closed to an open conformation which makes the active site accessible for substrates. While for many lipases crystal structures of the closed and open conformation have been determined, the pathway of the conformational transition and possible bottlenecks are unknown.

Modeling structure and flexibility of Candida antarctica lipase B in organic solvents.

Background: The structure and flexibility of Candida antarctica lipase B in water and five different organic solvent models was investigated using multiple molecular dynamics simulations to describe the effect of solvents on structure and dynamics. Interactions of the solvents with the protein and the distribution of water molecules at the protein surface were examined.

Results: The simulated structure was independent of the solvent, and had a low deviation from the crystal structure.

Rational design of a new one-step purification strategy for Candida antarctica lipase B by ion-exchange chromatography.

A fast and efficient one-step method for purification of lipase B from Candida antarctica by ion-exchange chromatography was developed by rational design. The electrostatic properties of the enzyme were calculated and validated by isoelectric focusing and measurement of the titration curve. C.