豌豆蚜触角转录组化学感受蛋白的鉴定、表达和结合特性分析

[目的]本研究旨在鉴定豌豆蚜Acyrthosiphon pisum触角转录组中化学感受蛋白(chemosensory protein,CSP)基因,明确触角中高表达的豌豆蚜CSP蛋白与蚜虫报警信息素、性信息素以及植物挥发物的分子结合特性.[方法]通过对豌豆蚜成蚜触角进行转录组测序,鉴定触角中候选CSP基因;采用RPKM...     

高原鼢鼠prestin基因的组织特异性表达与适应地下生活的关系

高原鼢鼠是青藏高原特有的地下鼠,地下鼠具有准确的空间定位能力。prestin蛋白是在耳蜗特异性表达且与回声定位有关的蛋白分子。为了探讨prestin基因与高原鼢鼠地下空间定位之间的关系,我们克隆了高原鼢鼠prestin基因的编码区序列,并与其他物种的prestin基因序列进行序列比对;运用PAML软件对高原鼢鼠的prestin基因进行进化分析;根据已克隆的序列,应用实时荧光定量的方法测定高原鼢鼠耳蜗、尾部、足垫和鼻垫组织中prestin基因mRNA的表达水平。研究结果表明,与人、大鼠、小鼠、裸鼢鼠、家兔和牛6种哺乳类动物相比,高原鼢鼠prestin基因编码的氨基酸序列显示存在9个氨基酸残基突变;Test2模型未检测到统计上显著的正选择位点;高原鼢鼠耳蜗prestin基因mRNA的表达水平显著高于高原鼠兔(P<0.05),高原鼢鼠耳蜗和尾部prestin基因mRNA的表达水平显著高于足垫和鼻垫（P<0.01）。以上结果说明,prestin基因不仅在高原鼢鼠耳蜗中表达,而且在尾部、足垫和鼻垫组织中也有表达。高原鼢鼠在地下洞道生活过程中,可能利用尾巴、前后足和鼻子辅助感知低频声波,从而准确地进行空间定位。     

人工巢箱条件下杂色山雀的巢位选择及其对繁殖成功率的影响

杂色山雀(Parus varius)是一种分布区域极其狭窄的小型森林洞巢鸟类,种群数量稀少,在中国大陆仅见繁殖于辽宁省的东南部山区和毗邻辽宁的吉林省西南部山区,为当地留鸟.为了探讨巢址选择对杂色山雀繁殖的影响,找出影响杂色山雀繁殖成功率的巢址选择方面的主要因子,于2009-2011年3-7月,在辽宁省仙人洞国家级自然保护区通过悬挂人工巢箱,进行杂色山雀对人工巢箱的巢址选择以及不同的巢址对杂色山雀繁殖成功率的影响研究.研究表明:杂色山雀多在针阔混交林中活动和繁殖,对位于赤松与蒙古栎混交林中的巢箱有一定偏好.野外共发现24巢杂色山雀在人工巢箱中繁殖,其中15巢繁殖成功,9巢繁殖失败.对杂色山雀利用的巢址样方主成分分析表明,巢位因子( 19.826％)、乔木因子(17.571％)、灌木因子(13.11％)、光照因子(11.587％)、隐蔽因子(10.562％)和边缘效应因子(7.572％)是影响杂色山雀对人工巢箱选择的重要因子.利用巢箱与对照巢箱相比,两者在距水源距离、距路距离、乔木平均高度、灌木平均高度和植被类型这5个环境变量上存在显著差异.繁殖成功巢与繁殖失败巢相比,繁殖成功的巢箱所在位置距路稍远,坡度较高,乔木最大高度较高,灌木盖度略低于繁殖失败巢箱.人为干扰和天敌捕食是造成杂色山雀繁殖失败的主要原因.以上研究结果表明,巢向偏南、距地面2 m以上、周围乔木高大、灌木平均高度大于1.5m、盖度在45％-55％之间、距水源20 m左右、距路20 m以外的位于针阔混交林边缘的巢箱是杂色山雀繁殖的最优巢址.目前杂色山雀的种群数量还很稀少,希望本研究能对这一珍稀鸟类的保护提供重要参考.     

利用肝脏转录组数据分析地山雀的适应性进化

肝脏是生物新陈代谢的重要器官。为了探究青藏高原特有鸟类地山雀(Parus humilis)如何适应低温、低氧等恶劣环境,我们对其肝脏转录组数据进行分析,并结合斑胸草雀基因组数据进行了比较研究。结果显示,地山雀肝脏转录组中的大部分高表达基因都直接参与机体的新陈代谢活动;通过与斑胸草雀基因组数据进行比较,对筛选出的214个快速进化基因进行代谢通路的功能富集,发现多数基因富集到与能量代谢、免疫反应和消化相关的通路上。本研究表明,高表达基因的功能一方面验证了肝脏是机体新陈代谢的主要场所,参与胆汁分泌、脂肪酸的转化及解毒等多项生理活动;另一方面也说明这些高表达基因对于维持肝脏的正常功能是必要的。快速进化基因的功能富集分析揭示了地山雀中与能量代谢、免疫反应和食性等相关的基因受到自然选择压力的影响而发生了适应性的快速进化。     

黄腹山雀的鸣唱特征分析

2006年4—5月及2007年6月,在北京小龙门林区录制了黄腹山雀(Parus venustulus)的鸣唱,利用Avisoft-SASLab Pro鸟声声谱分析软件(德国)测量鸣唱特征参数后进行统计分析,发现该地区的黄腹山雀种群鸣唱句法简单,鸣唱句子均为相同音节的不断重复。所采集的音节曲目中包含了56种音节型,音节类型数与采样个体数(r=0.973,P=0.000<0.05)呈显著正相关,不同个体的领域性鸣唱存在显著差异。与同域分布的大山雀、褐头山雀、煤山雀、沼泽山雀相比较,黄腹山雀的鸣唱句子最短(Dv=0.83±0.48),频率较高(Fmax=7.64±1.01,Fmin=3.27±1.13),句子中音节的重复次数最少(Ns.v=2.0±0.2)。     

人工巢箱中大山雀和褐头山雀的繁殖比较

2009年3-7月,在北京小龙门森林公园悬挂人工巢箱,对大山雀(Parus major)和褐头山雀(P.montanus;)的繁殖进行比较研究.野外共悬挂100个巢箱,其中19巢(19.0%)被大山雀、11巢(11.0%)被褐头山雀进驻,总利用率为30.0%.同域繁殖的大山雀和褐头山雀在窝卵数、孵化期上有极显著差异(P＜0.01),其中大山雀的窝卵数(8.21枚±0.25枚,n=19)极显著大于褐头山雀(6.18枚±0.23枚,n=11),而褐头山雀的孵化期(14.22d±0.44d,n=10)极显著长于大山雀(13.17 d±O.83 d,n=12).两者在卵重、卵大小、出雏数、雏鸟出飞数上无显著差异(P＞0.05).大山雀的繁殖成功率(27.0%)和营巢成效(63.2%)均显著低于褐头山雀(54.5%和100%)(P＜0.01).表明大山雀可能采取高产卵数、低存活率的繁殖对策,而褐头山雀的繁殖策略则可能为低产卵数、高存活率.     

高原低氧对大鼠大脑皮质生长休止蛋白7表达的影响

目的 探讨高原低氧对大鼠大脑皮质生长休止蛋白7(Gas7)表达的影响.方法 36只大鼠随机分为正常对照组和模拟高原低氧组,模拟高原低氧组大鼠进行6周缺氧,复制慢性高原低氧动物模型.实验结束后,所有动物采用免疫组织化学和免疫印迹技术检测大鼠大脑皮质中Gas7的表达.结果 与对照组相比,Gas7在模拟高原低氧组大鼠大脑皮质的表达明显增强.结论 Gas7可能参与了高原低氧对大鼠大脑皮质神经元结构和功能的影响.     

太白山南坡夏秋季鸟类组成

太白山是秦岭山脉的主峰, 生物区系成分复杂。为了研究太白山鸟类区系在过去20年间的变化, 我们于2007年5–7月(夏季)和9–10月(秋季), 根据海拔和典型植被在太白山南坡选定5种生境类型(退耕林、阔叶林、混交林、针叶林和高山灌丛草甸), 并在各种生境中选择样区采用样线法对鸟类组成进行调查。两个季节共观察到鸟类122种, 其中留鸟85种, 夏候鸟31种, 冬候鸟1种, 旅鸟5种。不同的生境类型中优势种和常见种不同, 而且在夏秋两季也有变化。中低海拔退耕林带鸟类物种数最多, 夏季有60种, 优势种为绿背山雀(Parus monticolus)、黄腹山雀(P. venustulus)和冠纹柳莺(Phylloscopus reguloides); 秋季有59种, 优势种为大山雀(Parus major)。中海拔阔叶林带夏季有鸟类40种, 优势种为绿背山雀、黄腹山雀和异色树莺(Cettia flavolivaceus); 秋季37种, 优势种是黄腹山雀、黑冠山雀(Parus rubidiventris)和银脸长尾山雀(Aegithalos fuliginosus)。 中高海拔针阔混交林带夏季有46种, 优势种是黄腰柳莺(Phylloscopus proregulus)、极北柳莺(P. borealis)和黑冠山雀; 秋季有37种, 优势种是黑冠山雀、褐冠山雀(Parus dichrous)和长尾山椒鸟(Pericrocotus ethologus)。高海拔针叶林带夏季有36种, 优势种是黄腰柳莺和黑冠山雀; 秋季有27种, 优势种是血雉(Ithaginis cruentus)和黑冠山雀。高山灌丛草甸带物种最少, 夏秋季都只有7种。各生境中鸟类物种组成的季节周转率随着海拔的升高而下降, 物种丰富度也呈现同样的趋势。太白山南北坡鸟类物种组成有较高的相似性。与20年前相比, 尽管在每种生境类型中优势种和常见种的组成仍相似, 但太白山南北坡的鸟类物种组成有较大的变化。     

高原鼢鼠神经型一氧化氮合酶基因编码区序列克隆与分析

高原鼢鼠是青藏高原特有的地下鼠,受到高原低氧以及洞穴低氧的双重低氧环境压力。经RNA 提取、RT-PCR、亚克隆与测序,本研究获得高原鼢鼠神经型一氧化氮合酶(nNOS)的编码区序列,并对其分子特征进行了分析。结果显示:高原鼢鼠nNOS 基因编码区(CDS)全长4 290 bp,编码1 429 个氨基酸残基;CDS 与大鼠、小鼠、兔、狗、人的同源性分别为90% 、89% 、87% 、87% 、89% ;结构域上,高原鼢鼠nNOS 具有PDZ蛋白结构域、氧化域、还原域及钙调素结合位点等nNOSs 所具有的典型结构域;基于nNOS 的最大似然树和贝叶斯树均支持高原鼢鼠与大鼠、小鼠具有最近的亲缘关系,与形态或其它分子标记构建的进化关系相符;分子进化分析检测到高原鼢鼠nNOS 中存在3 个正选择位点---332 T、1200 G 和1334 P,但均未达到统计显著水平。本研究为揭示高原鼢鼠nNOS 的表达特征及其在低氧适应中的作用与调控机制研究奠定了初步基础。     

瓦屋山2种山雀的生态位分化和共存

黑冠山雀(Parus rubidiventris)和煤山雀(P.ater)在瓦屋山同域分布,生态位相似,是潜在的竞争者。在垂直分布上,煤山雀的生态位宽度为5.237,显著高于黑冠山雀的2.792,而在水平分布和活动基质2个维度上,二者的生态位宽度值相当。尽管3个维度上2种山雀生态位重叠值均大于0.7,但是它们对3个维度上的资源利用分别存在不同的偏好和侧重。2种山雀的身体量度除了喙宽外均有极显著差异,这应该是2种山雀对环境适应的结果。这2种山雀在巢址选择上各项参数差异均不显著,表明适宜的洞巢可能是它们种间竞争的主要对象。2种山雀的种群数量可能与居留类型有关。空间生态位或食物生态位的分离及适宜的种群数量和比例是它们得以共存的几个重要因素。     

Oxidation and Cross-Linking of Human Hemoglobins by Activated Oxygen Species

The effect of activated oxygen species on human hemoglobins was studied. All radicals induced polymerization in Hb A both intermolecular and by cross-linking of subunits (intramolecular). However, a system producing mainly superoxide ion gave the most important changes. An oxidation step is necessary to produce polymerization since in the case of cyanmet Hb A (where there is no possible oxidation) no polymerization occurs. The effect of O^-₂ on blocked SH β 93 Hbs or on the abnormal Hbs tested was practically identical to that on Hb A although their autoxidation rates were modified. Consequently the action of radicals is different from autoxidation processes and the modified residues in the abnormal hemoglobins are not involved in the action of superoxide ion on Hb.

The kinetics of oxidation of Hb by H₂O₂ followed two steps: the first is the oxidation of oxy Hb to ferri Hb and the second is hemichrome formation. This last step is independent of the presence of H₂O₂ since it is not inhibited by catalase. The kinetics of oxidation to ferri Hb were of second order and the rate constant was found to be 16 M^-1 sec^-1.     

Biochemical Characterization of Hemoglobins from Caspian Sea Sturgeons (<Emphasis Type="Italic">Acipenser persicus and Acipenser stellatus</Emphasis>)

Hemoglobin (Hb) variability is a commonly used index of phylogenetic differentiation and molecular adaptation in fish enabling them to adapt to different ecological conditions. In this study, the characteristics of Hbs from two Sturgeon species of the Southern Caspian Sea Basin were investigated. After extraction and separation of hemoglobin from whole blood, the polyacrylamide gel electrophoresis (SDS-PAGE), cellulose acetate electrophoresis, and isoelectric focusing (IEF) were used to confirm Hb variabilities in these fishes. We showed that although both species have variable Hbs with different isoelectric points, their dominant Hbs can be identified. Ion exchange on CM-cellulose chromatography was used for purification of the dominant Hbs from these fishes. The accuracy of the methods was confirmed by IEF and SDS-PAGE. Spectral studies using fluorescence spectrophotometery indicated that although the Hbs from these fishes had similar properties they exhibited clear differences with human Hb. A comparative study of Hbs alpha-helix secondary substructures was performed by circular dichroism spectropolarimetry (CD) analysis. UV–vis spectrophotometery was also utilized to measure oxygen affinity of Hbs by sodium dithionite. Oxygen affinities of these Hbs were compared using Hb–oxygen dissociation curves. Together, these results demonstrate a significant relationship between oxygen affinity of fish hemoglobins and environmental partial pressure of oxygen.     

Combining the influence of two low O2 affinity-inducing chemical modifications of the central cavity of hemoglobin

HexaPEGylated hemoglobin (Hb), a non-hypertensive Hb, exhibits high O2 affinity, which makes it difficult for it to deliver the desired levels of oxygen to tissues. The PEGylation of very low O2 affinity Hbs is now contemplated as the strategy to generate PEGylated Hbs with intermediate levels of O2 affinity. Toward this goal, a doubly modified Hb with very low O2 affinity has been generated. The amino terminal of the beta-chain of HbA is modified by 2-hydroxy, 3-phospho propylation first to generate a low oxygen affinity Hb, HPPr-HbA. The oxygen affinity of this Hb is insensitive to DPG and IHP. Molecular modeling studies indicated potential interactions between the covalently linked phosphate group and Lys-82 of the trans beta-chain. To further modulate the oxygen affinity of Hb, the alpha alpha-fumaryl cross-bridge has been introduced into HPPr-HbA in the mid central cavity. The doubly modified HbA (alpha alpha-fumaryl-HPPr-HbA) exhibits an O2 affinity lower than that of either of the singly modified Hbs, with a partial additivity of the two modifications. The geminate recombination and the visible resonance Raman spectra of the photoproduct of alpha alpha-fumaryl-HPPr-HbA also reflect a degree of additive influence of each of these modifications. The two modifications induced a synergistic influence on the chemical reactivity of Cys-93(beta). It is suggested that the doubly modified Hb has accessed the low affinity T-state that is non-responsive to effectors. The doubly modified Hb is considered as a potential candidate for generating PEGylated Hbs with an O2 affinity comparable to that of erythrocytes for developing blood substitutes.     

Tangential flow filtration facilitated fractionation and PEGylation of low and high-molecular weight polymerized hemoglobins and their biophysical properties

Various types of hemoglobin (Hb)-based oxygen carriers (HBOCs) have been developed as red blood cell substitutes for treating blood loss when blood is not available. Among those HBOCs, glutaraldehyde polymerized Hbs have attracted significant attention due to their facile synthetic route, and ability to expand the blood volume and deliver oxygen. Hemopure®, Oxyglobin®, and PolyHeme® are the most well-known commercially developed glutaraldehyde polymerized Hbs. Unfortunately, only Oxyglobin® was approved by the FDA for veterinary use in the United States, while Hemopure® and PolyHeme® failed phase III clinical trials due to their ability to extravasate from the blood volume into the tissue space which facilitated nitric oxide scavenging and tissue deposition of iron, which elicited vasoconstriction, hypertension and oxidative tissue injury. Fortunately, conjugation of poly (ethylene glycol) (PEG) on the surface of Hb is capable of reducing the vasoactivity of Hb by creating a hydration layer surrounding the Hb molecule, which increases its hydrodynamic diameter and reduces tissue extravasation. Several commercial PEGylated Hbs (MP4®, Sanguinate®, Euro-PEG-Hb) have been developed for clinical use with a longer circulatory half-life and improved safety compared to Hb. However, all of these commercial products exhibited relatively high oxygen affinity compared to Hb, which limited their clinical use. To dually address the limitations of prior generations of polymerized and PEGylated Hbs, this current study describes the PEGylation of polymerized bovine Hb (PEG-PolybHb) in both the tense (T) and relaxed (R) quaternary state via thiol-maleimide chemistry to produce an HBOC with low or high oxygen affinity. The biophysical properties of PEG-PolybHb were measured and compared with those of commercial polymerized and PEGylated HBOCs. T-state PEG-PolybHb possessed higher hydrodynamic volume and P₅₀ than previous generations of commercial PEGylated Hbs. Both T- and R-state PEG-PolybHb exhibited significantly lower haptoglobin binding rates than the precursor PolybHb, indicating potentially reduced clearance by CD163 + monocytes and macrophages. Thus, T-state PEG-PolybHb is expected to function as a promising HBOC due to its low oxygen affinity and enhanced stealth properties afforded by the PEG hydration shell.     

Structural studies on a low oxygen affinity hemoglobin from mammalian species: Sheep (Ovis aries)

Hemoglobin (Hb) is in equilibrium between low affinity Tense (T) and high affinity Relaxed (R) states associated with its unliganded and liganded forms, respectively. Mammalian species can be classified into two groups on the basis of whether they express ‘high’ and ‘low’ oxygen affinity Hbs. Although Hbs from former group have been studied extensively, a limited number of structural studies have been performed for the low oxygen affinity Hbs. Here, the crystal structure of low oxygen affinity sheep methemoglobin (metHb) has been determined to 2.7 Å resolution. Even though sheep metHb adopts classical R state like quaternary structure, it shows localized quaternary and tertiary structural differences compared with other liganded Hb. The critical group of residues in the “joint region”, shown as a major source of quaternary constraint on deoxyHb, formed unique interactions in the α1β2/α2β1 interfaces of sheep metHb structure. In addition, the constrained β subunits heme environment and the contraction of N-termini and A-helices of β subunits towards the molecular dyad are observed for sheep metHb structure. These observations provide the structural basis for a low oxygen affinity and blunt response to allosteric effector of sheep Hb.     

不同功率的激光刺激对小鼠C2C12成肌细胞耗氧率水平的影响及机制

目的：探讨不同功率的低强度650 nm激光刺激对C₂C₁₂成肌细胞耗氧率水平和相关蛋白的影响及其机制。方法：以体外培养的C₂C₁₂小鼠成肌细胞作为实验对象,以4×10⁵个/孔接种于牵张6孔板中,采用输出功率5 mW,波长650 nm的二极管激光进行单次刺激,激光照射剂量分别0 J/cm²（0 min）、0.4 J/cm²（12.8 min）、0.8 J/cm²（25.6 min）。实验结束后,采用耗氧率试剂盒（Luxcel Biosciences）检测细胞耗氧率;提取细胞总蛋白,采用Western blot技术检测成肌调节因子（MyoD）、过氧化物酶体增殖活化受体γ共激活因子1α（PGC-1α）、雷帕霉素靶蛋白和磷酸化蛋白（p-mTOR/mTOR）表达。结果：与对照组相比,低剂量组细胞氧化耗氧率结果、MyoD、PGC-1α蛋白表达显著增加（P<0.05）,高剂量组MyoD、PGC-1α蛋白表达显著增加（P<0.05）,p-mTOR/mTOR蛋白显著降低（P<0.05）。结论：较低剂量（0.4 J/cm²）的650 nm低强度激光增强了细胞氧化功能水平,并对细胞分化相关蛋白有一定影响。其机制可能与适宜的激光刺激影响PGC-1α蛋白的表达,进而影响线粒体氧化呼吸有关。     

Functional characterization of fetal and adult yak hemoglobins: an oxygen binding cascade and its molecular basis

In contrast to most other mammals, the yak, which is native to high altitudes, has two major fetal and two or four major adult hemoglobin (Hb) components. We report the oxygen affinities and sensitivities to pH and 2,3-diphosphoglycerate of the two fetal and two adult Hbs commonly found in calves, compared to those of adult cow Hb A, and relate these findings to their primary structures and to placental maternal-fetal oxygen transfer at altitude. Arranged in order of decreasing oxygen affinity the Hbs are F1 (alpha I2 gamma 2), F2 (alpha II2 gamma 2), A1 (alpha II2 beta II2), and cow Hb A. The higher affinity of the fetal than the adult yak Hbs correlates with the beta 15Trp----Phe substitution, whereas the higher affinity in yak than in cow Hb correlates with the beta 135Ala----Val substitution. The difference in oxygen affinities between yak Hbs A1 and A2, which have identical beta chains, suggests the existence of yet unknown mechanisms determining oxygen affinity. The larger Bohr effects of F2 than F1 and of A2 than A1 are attributable to alpha-chain differences, most probably the alpha I50Glu----alpha II50His substitution.     

新型菜豆环氧化物水解酶的异源表达及对映归一性催化特性

为挖掘新型环氧化物水解酶（EH）,探讨其对映归一性催化特性,以菜豆（Phaseolus vulgaris）总RNA为模板,采用RT-PCR扩增了一种菜豆EH（PvEH1）的编码基因pveh1,并将其在大肠杆菌BL21（DE3）中进行了表达。一级和三维结构分析表明,PvEH1与绿豆和苜蓿EHs的同源性分别为85.7和81.1%,其催化三联体为Asp¹⁰¹-His²⁹⁹-Asp²⁶⁴,属于α/β水解酶超家族。当PvEH1催化外消旋环氧苯乙烷水解的转化率达99.1%时,产物（R）-苯乙二醇的对映体纯度为33.6% e.e._p。PvEH1对（S）-和（R）-SO的区域选择性系数α_S和β_R分别为91.1和53.3%。PvEH1的挖掘及其对映归一性催化特性的分析不仅增加了此类植物EHs的数目,而且为其归一性催化机制的研究和区域选择性的改造奠定了基础。     

环境因子对国华电厂温排水海域浮游动物群落β多样性的影响

对象山港国华电厂温排水海域10个站位的浮游动物进行了季节性采样.通过合并丰度数据、结合现场环境因子,应用广义非相似性模型(GDM)分析了环境因子对浮游动物β多样性的影响.结果表明： 共检出95种浮游动物,隶属于14个类群.该海域以小型浮游动物为主(丰度比例占62.6%),成体类群中以桡足类为主(丰度占35.3%).按照Whittaker多样性定义和加性分配,该海域α多样性比例占36.3%,β多样性比例为63.7%.在β多样性比例中,由环境因子引起的β多样性占43.8%,采样点间地理距离对β多样性无影响,未能解释比例占19.9%.据GDM拟合,有9个环境变量对浮游动物β多样性有影响,可解释β多样性比例为68.8%.在这些变量中,依贡献从高到低为季节水温、溶解氧、海域增温、电导率、悬浮颗粒物、盐度、透明度、水深和氧化还原电位,其中,季节水温、溶解氧和海域增温是驱动β多样性变化最重要的环境因子,对可解释β多样性比例的绝对贡献分别占23.9%、13.7%和9.7%.在变量梯度响应中,季节水温低于25 ℃、溶解氧高于5 mg·L^-1、海域增温超过1 ℃时,β多样性随变量梯度增加而快速增加.其他各预测变量对β多样性影响较小.     

定点突变提高环氧化物水解酶AuEH2催化对甲基苯基缩水甘油醚的对映选择性*

环氧化物水解酶可催化外消旋环氧化物的动力学拆分或对映归一性水解制备手性环氧化物或邻二醇,具有广阔的应用前景.为提高宇佐美曲霉环氧化物水解酶 (AuEH2) 催化外消旋对甲基苯基缩水甘油醚 (rac-pMPGE) 的对映体选择率 (E).通过分子动力学模拟 (MD) 选取相互作用频率最高的位点A250替换为其他19种氨基酸;选取对映选择性显著提高的突变体测定其动力学参数 (K_m和k_cat) 及区域选择性系数 (β_S和β_R),并利用重组大肠杆菌全细胞拆分rac-pMPGE.突变体AuEH2^A250H的E值从12.7提高至38.4,重组菌比活力为51.9U/g湿细胞;其水解 (S)-pMPGE的k_cat/K_m从10.0mmol/(L·s)提高至12.8 mmol/(L·s),而水解 (R)-pMPGE的k_cat/K_m从1.13mmol/(L·s)降低至0.35mmol/(L·s);全细胞拆分20mmol/L rac-pMPGE获得 (R)-pMPGE的ee_s为>99%,产率从33.0% 提高至40.7%.A250位点的突变对AuEH2的对映选择性和酶活力具有显著影响;高对映选择性的AuEH2突变体在制备高光学纯的 (R)-pMPGE中具有应用潜力.