The crucial role of bacterial laccases in the bioremediation of petroleum hydrocarbons.

Laccases (EC 1.10.3.2) are a class of metallo-oxidases found in a variety of fungi, plants, and bacteria as well as in certain insects. They can oxidize a wide variety of organic compounds and can be widely applied in many fields, especially in the field of biodegradation and detoxification of environmental pollutants. The practical efficacy of laccases depends on their ability to capture the target substance as well as their catalytic activity, which is related to their catalytic center, substrate selectivity, and substrate tolerance. Over the past few decades, many laccases have been identified in plants and fungi. Concurrently, bacterial laccases have received increasing attention because of their high thermostability and high tolerance to organic compounds. The aim of this review is to summarize the role of bacterial laccases in the bioremediation of petroleum hydrocarbons and to outline the correlation between the molecular structure of the mononuclear T1 Cu center of bacterial laccases and their substrate preference.

The protective effects and underlying mechanism of an anti-oligomeric Aß42 single-chain variable fragment antibody.

Oligomeric Aß42 aggregates have been identified as one of the major neurotoxic components of Alzheimer's disease (AD). Immunotherapy targeted against these Aß42 aggregates has been proposed as an appropriate therapeutic approach for the treatment of AD. Here, we report an anti-oligomeric Aß42 single-chain variable fragment (scFv) antibody, named MO6, obtained from the human antibody library of a healthy donor. ScFv MO6 specifically recognized and bound to the oligomeric Aß42 (Aß42 oligomers and immature protofibrils; 18-37 kDa), and reduced their levels mainly by blocking their formation, although scFv MO6 also induced disaggregation of Aß42 aggregates. More importantly, scFv MO6 ameliorated or attenuated Aß42-induced cytotoxicity and increased cell viability by up to 33%. Furthermore, scFv MO6 efficiently passed through an in vitro blood-brain barrier (BBB) model with a delivery efficiency of 66% after 60 min post-administration. ScFv MO6 is a monovalent antibody with an affinity constant (KD) of 5.2×10(-6) M for Aß42 oligomers. Molecular docking simulations of Aß42 to scFv MO6 revealed that the approach and specific binding of scFv MO6 to oligomeric Aß42 aggregates was achieved by conformational recognition and directed induction, which resulted in a more dynamic adaptation of Aß42 to scFv MO6, occurring mainly in the N-terminal (3-4), middle (12-19) and C-terminal (34-42) regions of Aß42. This binding mode of scFv MO6 to Aß42 explains its protective effects against oligomeric Aß42. Our findings may be applied for the design of a smaller antibody specific for Aß42 oligermers.