DL-天冬氨酸的红外和晶体结构研究

通过X-ray单晶衍射和IR对DL-天冬氨酸的结构进行表征,该有机化合物属单斜晶系,P21空间群,晶胞参数：a=5．1353（8）A,b=6.9713（11）A,c=76073（11）A,a=90°,β=9．812（3）°,严90° 分子式：C4H7NO4,Mr=133．11,V=268．36（7）A3,Z=2,Dc=1．647Mg／m^3,R1=0．0468,wR2=0．0683[I＞2σ（I）]。在晶体结构中,有机分子通过分子间氢键N-H…O和O-H…O组装成了三维网状的超分子结构。     

孔道层状己二酸多聚体的制备及晶体结构

采用水热法,以己二酸和水为原料,在碱性条件下,制备了一种新型的具有孔道二维层状己二酸多聚体。利用X-射线单晶衍射对其结构进行了测定,结果表明:该晶体属于单斜晶系,P1 21/c空间群,a=7.195(4),b=5.150(3),c=10.022(6),α=90.00°,β=111.019(9)°,γ=90.00°,V=346.65(30)3,Z=2,Dc=1.40002 g·cm3,F(000)=156,R gt(F)=0.0371,w R ref(F2)=0.0908。     

Liver Fatty Acid Binding Protein Gene-Ablation Exacerbates Weight Gain in High-Fat Fed Female Mice

Loss of liver fatty acid binding protein (L‐FABP) decreases long chain fatty acid uptake and oxidation in primary hepatocytes and in vivo. On this basis, L‐FABP gene ablation would potentiate high‐fat diet‐induced weight gain and weight gain/energy intake. While this was indeed the case when L‐FABP null (?/?) mice on the C57BL/6NCr background were pair‐fed a high‐fat diet, whether this would also be observed under high‐fat diet fed ad libitum was not known. Therefore, this possibility was examined in female L‐FABP (?/?) mice on the same background. L‐FABP (?/?) mice consumed equal amounts of defined high‐fat or isocaloric control diets fed ad libitum. However, on the ad libitum‐fed high‐fat diet the L‐FABP (?/?) mice exhibited: (1) decreased hepatic long chain fatty acid (LCFA) β‐oxidation as indicated by lower serum β‐hydroxybutyrate level; (2) decreased hepatic protein levels of key enzymes mitochondrial (rate limiting carnitine palmitoyl acyltransferase A1, CPT1A; HMG‐CoA synthase) and peroxisomal (acyl CoA oxidase 1, ACOX1) LCFA β‐oxidation; (3) increased fat tissue mass (FTM) and FTM/energy intake to the greatest extent; and (4) exacerbated body weight gain, weight gain/energy intake, liver weight, and liver weight/body weight to the greatest extent. Taken together, these findings showed that L‐FABP gene‐ablation exacerbated diet‐induced weight gain and fat tissue mass gain in mice fed high‐fat diet ad libitum—consistent with the known biochemistry and cell biology of L‐FABP.     

Synthesis of Diorganotin Esters of 5-Bromonicotinic Acid: X-ray Crystal Structure of Polymeric 5-Bromonicotinatodiorganotin

Two types of diorganotins [R₂Sn(OCOC₅H₃N-3-Br-5)₂] _n and {[R₂Sn(OH₂)(OCOC₅H₃N-3-Br-5)₂]₂} _n (R= Me, n-Bu, Ph, n-Oc), are prepared from 5-Br-omonicotinic acid and diorganotin oxides. All the compounds, 1–8, are characterized by elemental analysis as well as IR and ¹H-NMR spectroscopy. The crystal structures of [R₂Sn(OCOC₅H₃N-3-Br-5)₂] _n (2) and {[R₂Sn(OH₂)(OCOC₅H₃N-3-Br-5)₂]₂} _n (8) were determined by single crystal X-ray diffraction. In compound 2, each carboxylate moiety of 5-Br-omonicotinic acid is involved in coordination to one Sn atom via two O-atoms, and the N-atom of one pyridine-ring coordinates to the neighboring Sn atom which leads to a polymeric chain. And the N-atom of the other pyridine-ring is dissociative. In compound 8, the compound proves to be dinuclear macrocyclic compounds with 5-Br-omonicotinic acid bridging the adjacent tin atoms with a 12-member ring. The hydrogen bonds ( ) are observed in the compound 8. These intermolecular hydrogen bonds form another ring, and lead to a polymeric chain in the lattice at the same time. An erratum to this article can be found at     

Synthesis and Structure Characterization of Some Triorganotin Esters of Heteroaromatic Carboxylic Acid and Crystal Structure of Triphenyltin Esters of 6-Hydroxynicotinic Acid and 5-Chloro-6-hydroxynicotinic Acid

Reactions of (R₃Sn)₂O (R=Ph, 2-ClC₆H₄CH₂, 2-FC₆H₄CH₂, 4-CNC₆H₄CH₂) with 6-hydroxynicotinic acid and 5-chloro-6-hydroxynicotinic acid in 1:2 stoichiometry yielded eight triorganotin compounds. These compounds have been characterized by elemental analysis, IR and ¹H NMR spectroscopy. The crystal structures of triphenyltin esters of 6-hydroxynicotinic acid (1) and 5-chloro-6-hydroxynicotinic acid (2) were determined by single crystal X-ray diffraction. In these two compounds the tin atoms are rendered five-coordinate in a trigonal bipyramidal structure by coordination though the three phenyl carbon atoms and two oxygen atoms, one from carboxylate and other from the phenolic hydroxide. The resulting structures are two one-dimensional linear polymers through an interaction between the O atoms of phenolic hydroxide and tin atoms of an adjacent molecule.     

Structure Prediction of Partial-Length Protein Sequences

Protein structure information is essential to understand protein function. Computational methods to accurately predict protein structure from the sequence have primarily been evaluated on protein sequences representing full-length native proteins. Here, we demonstrate that top-performing structure prediction methods can accurately predict the partial structures of proteins encoded by sequences that contain approximately 50% or more of the full-length protein sequence. We hypothesize that structure prediction may be useful for predicting functions of proteins whose corresponding genes are mapped expressed sequence tags (ESTs) that encode partial-length amino acid sequences. Additionally, we identify a confidence score representing the quality of a predicted structure as a useful means of predicting the likelihood that an arbitrary polypeptide sequence represents a portion of a foldable protein sequence (“foldability”). This work has ramifications for the prediction of protein structure with limited or noisy sequence information, as well as genome annotation.     

Tin(IV) Polymers: Part 1. Synthesis of Diorganotin Esters of Thiosalicylic Acid: X-ray Crystal Structure of Polymeric Thiosalicylatodiorganotin

Thiosalicylatodiorganotin, [R₂Sn(O₂CC₆H₄S)]_n, (R=Me (1), n-Bu (2), Ph (3), 3-Cl–PhCH₂ (4)), are prepared from thiosalicylic acid and diorganotin chlorides. All the compounds, 1–4, are characterized by elemental analysis as well as IR and ¹H-NMR spectroscopy. X-ray crystallographic analysis of the 2 and 4 shows that the structures are polymeric with neighboring diorganotin centers being linked by one O-atom of the carboxylate ligands. The carboxylate moiety is involved in coordination to one Sn atom via one O-atom while the other O-atom coordinates to the neighboring Sn atom. The mercaptotropone sulfur atom is bonded to the central Sn atom thereby establishing that Sn is five-coordinate and exists in a trigonal bipyramidal geometry.     

Impact of Azidohomoalanine Incorporation on Protein Structure and Ligand Binding

The impact of the incorporation of a non‐natural amino acid (NNAA) on protein structure, dynamics, and ligand binding has not been studied rigorously so far. NNAAs are regularly used to modify proteins post‐translationally in vivo and in vitro through click chemistry. Herein, structural characterisation of the impact of the incorporation of azidohomoalanine (AZH) into the model protein domain PDZ3 is examined by means of NMR spectroscopy and X‐ray crystallography. The structure and dynamics of the apo state of AZH‐modified PDZ3 remain mostly unperturbed. Furthermore, the binding of two PDZ3 binding peptides are unchanged upon incorporation of AZH. The interface of the AZH‐modified PDZ3 and an azulene‐linked peptide for vibrational energy transfer studies has been mapped by means of chemical shift perturbations and NOEs between the unlabelled azulene‐linked peptide and the isotopically labelled protein. Co‐crystallisation and soaking failed for the peptide‐bound holo complex. NMR spectroscopy, however, allowed determination of the protein–ligand interface. Although the incorporation of AZH was minimally invasive for PDZ3, structural analysis of NNAA‐modified proteins through the methodology presented herein should be performed to ensure structural integrity of the studied target.     

免疫抑制酸性蛋白的分离纯化及鉴定

采用卵巢癌腹水为原料，经盐析、DEAE－52、SephadexG100、等电聚焦电泳，Sepharose4B反相免疫亲和层析技术，分离纯化出免疫抑制酸性蛋白（IAP）纯品，经8．0％聚丙烯酰胶凝胶电泳、免疫电泳和双向免疫交叉试验，证实其为单一成分；用此抗原免疫家兔，获得了IAP抗血清，其效价为1：32。     

两个苯并咪唑羧酸稀土配合物的合成、晶体结构及荧光性质

合成了1,3-二羧甲基苯并咪唑有机配体,并与氯化铕、氯化钐反应得到了两个新的稀土配合物,通过元素分析、X-射线单晶衍射及X-射线粉末衍射对其进行表征。晶体结构表明,两个配合物结构均为两个金属中心被4个配体桥联形成Ln_2O_8型双核次级结构基元,通过(κ~1-κ~1-μ_2)-(κ~1)-μ_3配位模式与配体形成(4,4)拓扑的二维网络结构。同时测定了这两个配合物的热稳定性及Eu配合物的荧光性质。     

牛奶蛋白纤维的结构性能及其应用

论述了牛奶蛋白纤维的发展历史。在形态结构中,通过扫描电子显微镜观察到纤维横截面呈扁平状,纵向有不规则的沟槽和海岛状的凹凸,其结晶结构存在明显的结晶和无定形的两相结构,并且有明显的结晶峰。分析了牛奶蛋白纤维的优良性能,探讨了其在纺织面料上的广泛应用。     

Branched-chain Amino Acid Biosensing Using Fluorescent Modified Engineered Leucine/Isoleucine/Valine Binding Protein

A novel fluorescence sensing system for branched-chain amino acids (BCAAs) was developed based on engineered leucine/isoleucine/valine-binding proteins (LIVBPs) conjugated with environmentally sensitive fluorescence probes. LIVBP was cloned from Escherichia coli and Gln149Cys, Gly227Cys, and Gln254Cys mutants were generated by genetic engineering. The mutant LIVBPs were then modified with environmentally sensitive fluorophores. Based on the fluorescence intensity change observed upon the binding of the ligands, the MIANS-conjugated Gln149Cys mutant (Gln149Cys-M) showed the highest and most sensitive response. The BCAAs Leu, Ile, and Val can each be monitored at the sub-micromolar level using Gln149Cys-M. Measurements were also carried out on a mixture of BCAFAs and revealed that Gln149Cys-M-based measurement is not significantly affected by the change in the molar ratio of Leu, Ile and Val in the sample. Its high sensitivity and group-specific molecular recognition ability make the new sensing system ideally suited for the measurement of BCAAs and the determination of the Fischer ratio, an indicator of hepatic disease involving metabolic dysfunction.     

A Novel 3D Europium (III) Coordination Polymer Constructed from 3,5-Pyridinedicarboxylate Acid: Synthesis, Crystal Structure and Emission Spectrum

Abstract  A novel 3D coordination polymer Eu₂(PDC)₃(H₂O)₃ (1) has been synthesized by hydrothermal reaction of europium chloride with 3,5-pyridinedicarboxylate acid (H₂PDC) under acidic condition (pH 2–3). Complex 1 is a 3D coordination polymer via 1D infinite chains built by the pyridinium moieties of the PDC²⁻ anions. The thermal analyses and luminescent properties of 1 have also been investigated. Graphical Abstract   A novel 3D coordination polymer Eu₂(PDC)₃(H2O)₃ has been synthesized by hydrothermal reaction of europium chloride with 3,5-pyridinedicarboxylate acid under acidic conditions (pH 2–3). The formation of the title complex demonstrates that pH plays an important role during the synthesis.      

甘草次酸的化学修饰和结构改造研究进展

甘草次酸是重要的医药中间体,具有广泛的用途和应用前景。该文综述了近几十年来甘草次酸的化学修饰和结构改造进展,为甘草次酸的进一步开发利用提供了参考。引用文献32篇。     

Fatty Acid Binding Domain Mediated Conjugation of Ultrafine Magnetic Nanoparticles with Albumin Protein

A novel bioconjugate of stearic acid capped maghemite nanoparticle (γ-Fe₂O₃) with bovine serum albumin (BSA) was developed by taking recourse to the fatty acid binding property of the protein. From FT-IR study, it was found that conjugation took place covalently between the amine group of protein molecule and carboxyl group of stearic acid capped maghemite nanoparticle. TEM study further signified the morphology of the proposed nanobioconjuagte. The binding constant of nanoparticle with protein molecule was evaluated from the optical property studies. Also, magnetic measurement (M–H) showed retaining of magnetic property by significant values of saturation magnetization and other hysteretic parameters.     

Common FABP4 Genetic Variants and Plasma Levels of Fatty Acid Binding Protein 4 in Older Adults

We examined common variants in the fatty acid binding protein 4 gene (FABP4) and plasma levels of FABP4 in adults aged 65 and older from the Cardiovascular Health Study. We genotyped rs16909187, rs1054135, rs16909192, rs10808846, rs7018409, rs2290201, and rs6992708 and measured circulating FABP4 levels among 3190 European Americans and 660 African Americans. Among European Americans, the minor alleles of six single nucleotide polymorphisms (SNP) were associated with lower FABP4 levels (all p ≤ 0.01). Among African Americans, the SNP with the lowest minor allele frequency was associated with lower FABP4 levels (p = 0.015). The C-A haplotype of rs16909192 and rs2290201 was associated with lower FABP4 levels in both European Americans (frequency = 16 %; p = 0.001) and African Americans (frequency = 8 %; p = 0.04). The haplotype combined a SNP in the first intron with one in the 3′untranslated region. However, the alleles associated with lower FABP4 levels were associated with higher fasting glucose in meta-analyses from the MAGIC consortium. These results demonstrate associations of common SNP and haplotypes in the FABP4 gene with lower plasma FABP4 but higher fasting glucose levels.     

4-氨基-1,2,4-三唑-3,5-二硝基苯甲酸盐的晶体结构、比热容及热力学性质

用4-氨基-1,2,4-三唑的甲醇溶液与3,5-二硝基苯甲酸的甲醇溶液合成了4-氨基-1,2,4-三唑-3,5-二硝基苯甲酸盐.室温下培养出单晶,通过X射线衍射测定晶体结构,晶体属于单斜系,空间群为G/c,晶胞参数为:a=1.8160(2) nm,b=0.4818(5)nm,c=2.6160(3) nm,α=γ=90°...     

硬脂酸对大豆蛋白质塑料性能的影响

对水的敏感性是阻碍大豆蛋白质降解塑料广泛应用的不利因素,为了克服这一缺点,实验固定甘油和大豆蛋白质的比例,通过添加硬脂酸与大豆蛋白质共混,研究了其添加量对机械性能和吸水率的影响。同时拉伸和红外、扫描电镜等实验表明甘油、硬脂酸对膜的力学性能、吸水率、断面形态、红外图谱均有影响。     

Fatty Acid Binding Protein-1 (FABP1) and the Human FABP1 T94A Variant: Roles in the Endocannabinoid System and Dyslipidemias

The first discovered member of the mammalian FABP family, liver fatty acid binding protein (FABP1, L‐FABP), occurs at high cytosolic concentration in liver, intestine, and in the case of humans also in kidney. While the rat FABP1 is well studied, the extent these findings translate to human FABP1 is not clear—especially in view of recent studies showing that endocannabinoids and cannabinoids represent novel rat FABP1 ligands and FABP1 gene ablation impacts the hepatic endocannabinoid system, known to be involved in non‐alcoholic fatty liver (NAFLD) development. Although not detectable in brain, FABP1 ablation nevertheless also impacts brain endocannabinoids. Despite overall tertiary structure similarity, human FABP1 differs significantly from rat FABP1 in secondary structure, much larger ligand binding cavity, and affinities/specificities for some ligands. Moreover, while both mouse and human FABP1 mediate ligand induction of peroxisome proliferator activated receptor‐α (PPARα), they differ markedly in pattern of genes induced. This is critically important because a highly prevalent human single nucleotide polymorphism (SNP) (26–38 % minor allele frequency and 8.3 ± 1.9 % homozygous) results in a FABP1 T94A substitution that further accentuates these species differences. The human FABP1 T94A variant is associated with altered body mass index (BMI), clinical dyslipidemias (elevated plasma triglycerides and LDL cholesterol), atherothrombotic cerebral infarction, and non‐alcoholic fatty liver disease (NAFLD). Resolving human FABP1 and the T94A variant's impact on the endocannabinoid and cannabinoid system is an exciting challenge due to the importance of this system in hepatic lipid accumulation as well as behavior, pain, inflammation, and satiety.