Amino terminal myristylation of the protein kinase p60src, a retroviral transforming protein

The transforming protein of Rous sarcoma virus, p60src, was shown to be acylated at its amino terminus with the long-chain fatty acid myristic acid by isolation of a tryptic peptide with the following structure: myristylglycylserylseryllysine. The occurrence of this unusual posttranslational modification in the cyclic adenosine monophosphate-dependent protein kinase and in several transforming protein kinases of mammalian retroviruses suggests that myristylation of the amino terminal glycyl residue may be critical for the function of certain proteins related to cell transformation and growth control.     

A calcium-dependent protein kinase with a regulatory domain similar to calmodulin.

Calcium can function as a second messenger through stimulation of calcium-dependent protein kinases. A protein kinase that requires calcium but not calmodulin or phospholipids for activity has been purified from soybean. The kinase itself binds calcium with high affinity. A complementary DNA clone for this kinase has been identified; it encodes a protein with a predicted molecular mass of 57,175 daltons. This protein contains a catalytic domain similar to that of calmodulin-dependent kinases and a calmodulin-like region with four calcium binding domains (EF hands). The predicted structure of this kinase explains its direct regulation via calcium binding and establishes it as a prototype for a new family of calcium-regulated protein kinases.     

野生大豆AP2/RAV亚家族转录因子GsRAV3负调控拟南芥对ABA的敏感性

RAV亚家族蛋白包括1个AP2 DNA结合域和1个B3 DNA结合域。研究表明,GsRAV3是植物响应碱和ABA胁迫的重要调节因子。在碱和ABA处理下,野生大豆根系GsRAV3基因被诱导上调表达。与野生型相比,超量表达野生大豆GsRAV3的拟南芥在ABA胁迫下种子萌发状况和幼苗鲜重指标表现良好,对ABA敏感性降低。进一步研究表明,GsRAV3基因超量表达显著影响ABA合成和应答相关基因表达量。此外,GsRAV3定位于植物细胞核中,但在酵母细胞中未表现出明显的转录激活活性。综上所述,GsRAV3可能通过影响ABA合成及应答相关基因转录水平降低植物对外源ABA敏感性,表明GsRAV3在种子萌发和幼苗早期ABA信号传递过程中发挥重要作用。     

The 2.6 angstrom crystal structure of a human A2A adenosine receptor bound to an antagonist

The adenosine class of heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) mediates the important role of extracellular adenosine in many physiological processes and is antagonized by caffeine. We have determined the crystal structure of the human A2A adenosine receptor, in complex with a high-affinity subtype-selective antagonist, ZM241385, to 2.6 angstrom resolution. Four disulfide bridges in the extracellular domain, combined with a subtle repacking of the transmembrane helices relative to the adrenergic and rhodopsin receptor structures, define a pocket distinct from that of other structurally determined GPCRs. The arrangement allows for the binding of the antagonist in an extended conformation, perpendicular to the membrane plane. The binding site highlights an integral role for the extracellular loops, together with the helical core, in ligand recognition by this class of GPCRs and suggests a role for ZM241385 in restricting the movement of a tryptophan residue important in the activation mechanism of the class A receptors.     

Production of 2-Keto-L-Gulonate, an Intermediate in L-Ascorbate Synthesis, by a Genetically Modified Erwinia herbicola

A new metabolic pathway has been created in the microorganism Erwinia herbicola that gives it the ability to produce 2-keto-L-gulonic acid, an important intermediate in the synthesis of L-ascorbic acid. Initially, a Corynebacterium enzyme that could stereoselectively reduce 2,5-diketo-D-gluconic acid to 2-keto-L-gulonic acid was identified and purified. DNA probes based on amino acid sequence information from 2,5-diketo-D-gluconic acid reductase were then used to isolate the gene for this enzyme from a Corynebacterium genomic library. The 2,5-diketo-D-gluconic acid reductase coding region was fused to the Escherichia coli trp promoter and a synthetic ribosome binding site and was then introduced into E. herbicola on a multicopy plasmid. Erwinia herbicola naturally produces 2,5-diketo-D-gluconic acid via glucose oxidation, and when recombinant cells expressing the plasmid-encoded reductase were grown in the presence of glucose, 2-keto-L-gulonic acid was made and released into the culture medium. The data demonstrate the feasibility of creating novel in vivo routes for the synthesis of important specialty chemicals by combining useful metabolic traits from diverse sources in a single organism.     

黄秋葵新品种‘闽秋葵2号’的选育

闽秋葵2号属于黄秋葵杂交一代新品种,该品种叶脉红色,侧枝多,产量高,较耐寒,果实光亮无刚毛,且不易老化;其株高1.6m,始花节位5~6,果淡紫红色、6~9棱,果长19cm,横径1.8cm,单果鲜重25g,2013-2014年参加福建省黄秋葵新品种区域试验,平均产量46 681.5kg·hm~(-2),比对照东园2号增产44.61%;2014-2015年参加福建省黄秋葵新品种生产性试验,平均产量达到41 089.5kg·hm~(-2),是一个优质高产抗病的黄秋葵新品种,2016年6月通过了福建省农作物品种审定委员会认定(闽认菜2016022)。     

Helix geometry, hydration, and G.A mismatch in a B-DNA decamer

The DNA double helix is not a regular, featureless barberpole molecule. Different base sequences have their own special signature, in the way that they influence groove width, helical twist, bending, and mechanical rigidity or resistance to bending. These special features probably help other molecules such as repressors to read and recognize one base sequence in preference to another. Single crystal x-ray structure analysis is beginning to show us the various structures possible in the B-DNA family. The DNA decamer C-C-A-A-G-A-T-T-G-G appears to be a better model for mixed-sequence B-DNA than was the earlier C-G-C-G-A-A-T-T-C-G-C-G, which is more akin to regions of poly(dA).poly(dT). The G.A mismatch base pairs at the center of the decamer are in the anti-anti conformation about their bonds from base to sugar, in agreement with nuclear magnetic resonance evidence on this and other sequences, and in contrast to the anti-syn geometry reported for G.A pairs in C-G-C-G-A-A-T-T-A-G-C-G. The ordered spine of hydration seen earlier in the narrow-grooved dodecamer has its counterpart, in this wide-grooved decamer, in two strings of water molecules lining the walls of the minor groove, bridging from purine N3 or pyrimidine O2, to the following sugar O4'. The same strings of hydration are present in the phosphorothioate analog of G-C-G-C-G-C. Unlike the spine, which is broken up by the intrusion of amine groups at guanines, these water strings are found in general, mixed-sequence DNA because they can pass by unimpeded to either side of a guanine N2 amine. The spine and strings are perceived as two extremes of a general pattern of hydration of the minor groove, which probably is the dominant factor in making B-DNA the preferred form at high hydration.     

极度濒危植物五针白皮松解剖生态学研究

与云南松和华山松比较,五针白皮松叶的生态解剖特点更接近云南松,具有更多的阳性叶特征,如表皮细胞大小、表皮和下皮的厚度等;叶肉组织致密度介于云南松和华山松之间;五针白皮松的气孔器大小是3 种松树中最大者,可能意味着五针白皮松适应更加湿润(降水量更大)凉爽的气候.五针白皮松对光、温度和水分的要求表明它可能更加适应高海拔生态条件,目前生境可能不是它最适宜的生活环境.     

果蔗2号新品系适应性栽培试验

果蔗2号新品系在贵州兴义、贞丰、关岭、习水的适应性栽培试验结果表明:果蔗2号在株高、茎径、田间锤度、有效茎及产量上均比对照黔糖3号和罗汉蔗具有优势,并具有抗寒、抗旱、耐水、耐肥、高产及糖分积累早的优良性状,适宜贵州蔗区和相应地区坝地和缓坡地种植,是优良的果糖兼用型蔗汁饮料用原料蔗。     

纤维用亚麻新品种吉亚2号选育报告

吉亚2号亚麻新品种是以K6897为母本,黑亚3号为父本杂交育成。经过3年省区域试验:平均原茎产量5532.7kg/hm2,比对照穴黑亚3号雪提高13.06%,长麻率为16.41%,比对照提高2.57个百分点,长麻产量为908.20kg/hm2,比对照提高36.07%;2年省生产示范试验:平均原茎产量为5525.85kg/hm2,比对照增产22.54%,长麻率为17%,比对照提高2.95个百分点,产麻量为934.05kg/hm2,比对照提高46%。     

Design, activity, and 2.8 A crystal structure of a C2 symmetric inhibitor complexed to HIV-1 protease

A two-fold (C2) symmetric inhibitor of the protease of human immunodeficiency virus type-1 (HIV-1) has been designed on the basis of the three-dimensional symmetry of the enzyme active site. The symmetric molecule inhibited both protease activity and acute HIV-1 infection in vitro, was at least 10,000-fold more potent against HIV-1 protease than against related enzymes, and appeared to be stable to degradative enzymes. The 2.8 angstrom crystal structure of the inhibitor-enzyme complex demonstrated that the inhibitor binds to the enzyme in a highly symmetric fashion.