Leucine-rich repeat C4 protein is involved in nervous tissue development and neurite outgrowth, and induction of glioma cell differentiation

LRRC4, leucine-rich repeat C4 protein, has been identified in human （GenBank accession No. AF196976）, mouse （GenBank accession No. DQ177325）, rat （GenBank accession No. DQ119102） and bovine （GenBank accession No. DQ 164537） with identical domains. In terms of their similarity, the genes encoding LRRC4 in these four mammalian species are orthogs and therefore correspond to the same gene entity. Based on previous research, and using in situ hybridization, we found that LRRC4 had the strongest expression in hippocampal CA1 and CA2, the granule cells of the dentate gyrus region, the mediodoral thalamic nucleus, and cerebella Purkinje cell layers. Using a P19 cell model, we also found that LRRC4 participates in the differentiation of neuron and glia cells. In addition, extracellular proteins containing both an LRR cassette and immunoglobulin domains have been shown to participate in axon guidance. Our data from neurite outgrowth assays indicated that LRRC4 promoted neurite extension of hippocampal neurons, and induced differentiation of glioblastoma U251 cells into astrocyte-like cells, confirmed by morphology observation and glial fibrillary acidic protein expression.     

酵母表面展示脂肪酶合成己二酸二异辛酯

展示酶的酵母细胞既具有固定化酶的优点,又有制备简单、成本较低的特点.采用表面展示南极假丝酵母脂肪酶B (Candida antarctica lipase B,CALB)的毕赤酵母细胞催化合成己二酸二异辛酯(Diisooctyl adipate,DIOA),对该反应体系进行优化,并实现了初步工艺放大制备.经条件优化后,在10mL反应体系中,DIOA的产率可达85.0％.该工艺放大到200mL反应体系时,DIOA产率可达97.8％.经减压蒸馏,DIOA纯度可达到98.2％.该酵母表面展示脂肪酶在合成绿色润滑油己二酸二异辛酯中具有良好应用前景.     

Lead generation of heat shock protein 90 inhibitors by a combination of fragment-based approach, virtual screening, and structure-based drug design

Heat shock protein 90 (Hsp90) is a molecular chaperone which regulates maturation and stabilization of its substrate proteins, known as client proteins. Many client proteins of Hsp90 are involved in tumor progression and survival and therefore Hsp90 can be a good target for developing anticancer drugs. With the aim of efficiently identifying a new class of orally available inhibitors of the ATP binding site of this protein, we conducted fragment screening and virtual screening in parallel against Hsp90. This approach quickly identified 2-aminotriazine and 2-aminopyrimidine derivatives as specific ligands to Hsp90 with high ligand efficiency. In silico evaluation of the 3D X-ray Hsp90 complex structures of the identified hits allowed us to promptly design CH5015765, which showed high affinity for Hsp90 and antitumor activity in human cancer xenograft mouse models.     

Periplasmic proteins of Escherichia coli are highly resistant to aggregation: reappraisal for roles of molecular chaperones in periplasm

Periplasmic proteins of Gram-negative bacteria like Escherichia coli are subjected to immediate affect of environmental fluctuation that may unfold proteins, due to the permeability of the outer membrane to small molecules. They are thus supposedly protected by certain molecular chaperones. Nevertheless, no homologues of typical molecular chaperones have so far been found in periplasm, and the recently reported chaperone activities of periplasmic protein disulfide isomerase (PDI) and peptidyl prolyl isomerase (PPI) seem to be too weak to satisfy such assumed needs. In an attempt to reveal whether periplasmic proteins exhibit certain unusual properties, we discovered that such proteins as a whole are highly resistant to aggregation under a wide variety of denaturing conditions. Furthermore, in an effort to unveil the nature behind this phenomenon we purified and examined four prominent periplasmic proteins. Our results demonstrate that these proteins unfold at rather mild denaturing conditions and expose hydrophobic surfaces during such unfolding process, but hardly form complexes with a typical molecular chaperone. Based on these observations, we propose that the periplasmic proteins have been evolved to resist the formation of aggregates when subjected to various denaturing conditions and molecular chaperones may thus not be needed in periplasm.     

Site-selective lateral multilayer assembly of bienzyme with polyelectrolyte on ITO electrode based on electric field-induced directly layer-by-layer deposition

We describe here a new approach to construct a multilayer enzyme/polyelectrolyte film on a structured transparent indium-tin oxide (ITO) covered glass electrode surface as micropattern, on which two different types of enzyme distributed laterally on one common substrate without interference. The multilayer film was prepared by alternate electric field directed layer-by-layer assembly deposition and alternate deposition of different redox enzymes and polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) onto the site-selective ITO glass electrode surface. The cyclic voltammogram, obtained from the ITO glass electrode modified with the glucose oxidase (GO(X))/PDDA and catalase (CA(T))/PDDA multilayers, revealed that the bioelectrocatalytic response is directly correlated to the number of deposition bilayers. From the analysis of cyclic voltammetric characterization, the coverage of catalytically active enzymes per enzyme/PDDA bilayer during the multilayer formation was homogeneous, which demonstrates that the multilayer is constructed in a spatially ordered manner. Also, from the atomic force microscopy and Brewster angle microscopy measurements, more information of the multilayer constructed by different methods on the modified electrode surface is obtained and compared. This fabrication technique is simple and would be applicable to the construction of a thickness- and area-controlled biopattern composed of multi-enzymes as well as multiple biomaterials.     

酿酒酵母在纤维素乙醇生产中对毒性化合物的耐受机理研究进展

利用木质纤维素生产燃料乙醇的过程中,前期预处理所产生的抑制剂会影响酵母的正常生长和后续的发酵过程。为减小抑制剂的影响所采取的一些脱毒策略往往造成糖的损失和生产成本的增加,这在实际生产与经济上是不可行的。因此,具有强的抑制剂耐受性的酿酒酵母菌株对于提高纤维素乙醇产率是十分重要的。近十年来,对于酿酒酵母胁迫耐受机制的研究取得了一些重要的进展,着重介绍目前酿酒酵母对抑制剂耐受机制的研究现状,包括一些关键性基因的表达及代谢通路过程分析等。同时也介绍一些应对抑制剂提高酵母发酵能力的措施。     

Plasmodium vivax: molecular cloning, expression and characterization of glutathione S-transferase

Malaria parasite glutathione S-transferases (GSTs) are postulated to be essential for parasite survival by protecting the parasite against oxidative stress and buffering the detoxification of heme-binding compounds; therefore, GSTs are considered potential targets for drug development. In this study, we identified a Plasmodium vivax gene encoding GST (PvGST) and characterized the biochemical properties of the recombinant enzyme. The PvGST contained 618 bp that encoded 205 amino acids and shared a significant degree of sequence identity with GSTs from other Plasmodium species. The recombinant homodimeric enzyme had an approximate molecular mass of 50kDa and exhibited GSH-conjugating and GSH-peroxidase activities towards various model substrates. The optimal pH for recombinant PvGST (rPvGST) activity was pH 8.0, and the enzyme was moderately unstable at 37 degrees C. The K(m) values of rPvGST with respect to GSH and CDNB were 0.17+/-0.09 and 2.1+/-0.4mM, respectively. The significant sequence homology and similar biochemical properties of PvGST and Plasmodium falciparum GST (PfGST) indicate that they may have similar molecular structures. This information may be useful for the design of specific inhibitors for plasmodial GSTs as potential antimalarial drugs.