花椰菜天然钙调素抗体的特性及其ELISA定量法的建立

钙调素是一种具有多种调节功能的钙结合蛋白质，其免疫原性很弱，本文采用两次基础免疫和多次加强免疫的方法，获得了免疫花椰菜天然钙调素抗血清，用免疫双扩散法鉴定，其效价为１：３２钙调节不易与固相载体结合，我们先用０．２％戊二醛处理聚苯乙烯板载体，再用于包被钙调素，在上述基础上建立了定量测定植物钙调素的竞争性酶联免疫吸附测定（ＥＬＩＳＡ）技术及检测动物血清中抗钙调素抗体的间接ＥＬＩＳＡ技术。     

ABA与Ca~(2+)-CaM对草莓叶片抗氧化防护酶系统影响

用外源植物激素脱落酸ABA(abscisic acid,ABA)处理草莓叶片,草莓体细胞的抗氧化防护酶活性升高,表明ABA作为植物信号分子可以诱导草莓这一对干旱较为敏感的植物的逆境响应.Fluridone处理未能抑制草莓细胞对外源ABA的响应.进一步研究表明,钙调素(Calmodulin,CaM)作为Ca2+传感蛋白,介导了草莓叶片细胞ABA的下游信号事件.     

Calmodulin modulation of ion channels and receptors

Ion channels and receptors are the structural basis for neural signaling and transmission. Recently, the function of ion channels and receptors has been demonstrated to be modulated by many intracellular and extracellular chemicals and signaling molecules. Increasing evidence indicates that the complexity and plasticity of the function of central nervous system is determined by the modulation of ion channels and receptors. Among various mechanisms, Ca 2+ signaling pathways play important roles in neuronal activity and some pathological changes. Ca 2+ influx through ion channels and receptors can modulate its further influx in a feedback way or modulate other ion channels and receptors. The common feature of the modulation is that Ca 2+ /calmodulin (CaM) is the universal mediator. CaM maintains the coordination among ion channels/receptors and intracellular Ca 2+ homeostasis by feedback modulation of ion channels/receptors activity. This review focuses on the modulating processes of ion channels and receptors mediated by CaM, and further elucidates the mechanisms of Ca 2+ signaling.     

卵菌菌丝顶端钙调素的免疫组织化学定位

采用胞壁水解酶（Ｄｒｉｓｅｌａｓｅ２ｍｇ·Ｌ－１）和甲醇（－２０℃），分别对卵菌（Ｓａｐｒｏｌｅｇｎｉａｆｅｒａｘ）菌丝细胞壁及细胞膜进行通透，然后用免疫组织化学法对菌丝钙调素（ＣａＭ）的分布进行定位．结果表明ＣａＭ较密集地分布在菌丝顶端和在菌丝旁侧新形成的侧枝，亚顶端次之，基部菌丝几乎无特异性染色．由此提示，ＣａＭ可能参与卵菌菌丝顶端生长的调控．     

Detailed Evidence for an Unparalleled Interaction Mode between Calmodulin and Orai Proteins

Calmodulin (CaM) binds most of its targets by wrapping around an amphipathic α‐helix. The N‐terminus of Orai proteins contains a conserved CaM‐binding segment but the binding mechanism has been only partially characterized. Here, microscale thermophoresis (MST), surface plasmon resonance (SPR), and atomic force microscopy (AFM) were employed to study the binding equilibria, the kinetics, and the single‐molecule interaction forces involved in the binding of CaM to the conserved helical segments of Orai1 and Orai3. The results consistently indicated stepwise binding of two separate target peptides to the two lobes of CaM. An unparalleled high affinity was found when two Orai peptides were dimerized or immobilized at high lateral density, thereby mimicking the close proximity of the N‐termini in native Orai oligomers. The analogous experiments with smooth muscle myosin light chain kinase (smMLCK) showed only the expected 1:1 binding, confirming the validity of our methods.     

Temperature dependences on the infrared spectra of some proteins

Recent developments of FT-IR and computer techniques made it possible to detect minute changes (temperature dependences etc.) in the infrared spectra of proteins in aqueous solution.In this paper we studied temperature dependences of the amide I and I bands of ribonuclease A (RNase A), calmodulin (CaM), and Ca²⁺-bound CaM in H₂O and D₂O solutions between 28°C and 70°C using the difference-spectrum and Fourier self-deconvolution techniques.     

油菜花粉钙结合蛋白的研究

以油菜花粉(Brassica campestris)为材料纯化了钙调素(CaM),并得到一种新钙结合蛋白(NCBP)。经SDS-PAGE、PAGE和等电聚焦电泳(IEF)鉴定,这两种蛋白质均表现均一。CaM分子量为18.8kD, NCBP为16.3kD,等电点分别为3.6和4.2。研究证明花粉CaM具有与其他来源CaM所特有的性质,对环核苷酸磷酸二酯酶(简称PDE)有明显的激活作用,而花粉NCBP不明显。花粉CaM在PAGE和SDS-PAGE中电泳行为有Ca²⁺效应,而NCBP仅表现在PAGE中。经氨基酸组成分析表明两种蛋白质氨基酸组成不同,但均含有较多的酸性氨基酸,不含Trp, 含1个Cys。CaM和NCBP N-端均为封闭,CaM C-端为-Met-Ala-Lys-COOH。两种蛋白质具有不同的肽谱和CD谱。用DTNB修饰花粉CaM Cys残基,则激活PDE的能力明显下降。