Structural Aspects and Prediction of Calmodulin-Binding Proteins

Calmodulin (CaM) is an important intracellular protein that binds Ca²⁺ and functions as a critical second messenger involved in numerous biological activities through extensive interactions with proteins and peptides. CaM’s ability to adapt to binding targets with different structures is related to the flexible central helix separating the N- and C-terminal lobes, which allows for conformational changes between extended and collapsed forms of the protein. CaM-binding targets are most often identified using prediction algorithms that utilize sequence and structural data to predict regions of peptides and proteins that can interact with CaM. In this review, we provide an overview of different CaM-binding proteins, the motifs through which they interact with CaM, and shared properties that make them good binding partners for CaM. Additionally, we discuss the historical and current methods for predicting CaM binding, and the similarities and differences between these methods and their relative success at prediction. As new CaM-binding proteins are identified and classified, we will gain a broader understanding of the biological processes regulated through changes in Ca²⁺ concentration through interactions with CaM.     

铝合金三角形波纹夹芯板对平头弹抗冲击特性数值模拟研究

为研究铝合金三角形波纹夹芯板对平头弹体的抗冲击性能及损伤特性，利用有限元软件ABAQUS/Explicit建立弹体冲击靶板的数值模拟模型，并结合实验验证了模型及其参数的有效性。基于数值计算结果，分析了三角形波纹夹芯板几何结构对其防护性能、失效模式和能量吸收的影响规律及机理，并与等面密度单层板进行对比分析，研究结果表明，靶体几何结构对其抗冲击性能存在影响，三角形波纹夹芯板抗冲击性能低于单层板抗冲击性能。此外，增加芯体拓扑结构夹角能显著提高三角形波纹夹芯板的抗冲击性能，并且靶板几何形状会对其失效模式及耗能特性存在影响。     

三角形微通道饱和沸腾传热系数的预测

基于以丙酮为工质的三角形截面微通道饱和沸腾传热的实验数据,通过最小二乘法对实验数据进行参数拟合,得到一组新的经验参数,结合Thome提出的预测圆形截面微通道饱和沸腾传热系数的三区模型,对微通道饱和沸腾的传热系数进行了预测。结果表明:该三区模型可以较好地预测出传热系数随着干度的变化趋势,并得到90.04%的实验值和预测值误差在30%之内,吻合度较好。     

Lysin Motif (LysM) Proteins: Interlinking Manipulation of Plant Immunity and Fungi

The proteins with lysin motif (LysM) are carbohydrate-binding protein modules that play a critical role in the host-pathogen interactions. The plant LysM proteins mostly function as pattern recognition receptors (PRRs) that sense chitin to induce the plant’s immunity. In contrast, fungal LysM blocks chitin sensing or signaling to inhibit chitin-induced host immunity. In this review, we provide historical perspectives on plant and fungal LysMs to demonstrate how these proteins are involved in the regulation of plant’s immune response by microbes. Plants employ LysM proteins to recognize fungal chitins that are then degraded by plant chitinases to induce immunity. In contrast, fungal pathogens recruit LysM proteins to protect their cell wall from hydrolysis by plant chitinase to prevent activation of chitin-induced immunity. Uncovering this coevolutionary arms race in which LysM plays a pivotal role in manipulating facilitates a greater understanding of the mechanisms governing plant-fungus interactions.     

三高测量技术探测岩溶

阐述了三高测量技术的内涵和特点，以珠江水泥厂岩溶探测为例，阐述了三高技术对溶岩探测的应用及效果，经处理直观，形象地反映了岩溶的发育分布情况及形态。     

一种新型格构式刚架平面外稳定的实用算法

截面为三角形的轻型空间格构式刚架的平面外整体稳定性是设计中必须考虑的问题。从结构的全过程分析着手 ,考虑几何非线性 ,经过大量的计算机分析 ,对这种结构体系的整体稳定性能进行了研究 ,并通过对所得数据的归纳和与等效实腹式刚架的比较 ,提出了一个简便可行的稳定验算方法。     

一类全系数模糊规划问题及其求解方法

模糊规划是不确定规划的重要一类,对许多带有模糊信息的实际问题都能进行有效地处理,对模糊规划的求解方法进行讨论不仅具有理论意义,还具有实际意义.为寻求一类全系数模糊规划问题的求解方法,利用三角(或梯形)模糊数的排序准则并结合禁忌搜索算法设计了一种求解系数均为三角(或梯形)模糊数的规划模型的人工智能算法.数值算例表明笔者所提方法行之有效.     

混合级联多电平逆变器混合频率载波调制技术

针对于Ⅱ型混合级联型多电平逆变器混合调制中,输出电平切换时出现的低压单元直流侧电流倒灌问题,提出了一种改进的混合频率载波调制策略.该策略采用频率相差1倍,且幅值相同的6个层叠载波对正弦调制波进行混合调制,兼顾了低压单元和高压单元的性能,在保障输出电压波形质量的同时,完全解决了电流倒灌问题.以Ⅱ型混合级联七电平逆变器为例,在给定相关参数下对该策略进行了仿真和实验验证,研究结果表明该策略下逆变器相电压和线电压总谐波畸变率分别为19.90％和17.34％,谐波主要分布在载波比两侧,直流侧电流倒灌问题被完全消除.     

Structural Analysis of the Complex between Penta-EF-Hand ALG-2 Protein and Sec31A Peptide Reveals a Novel Target Recognition Mechanism of ALG-2

ALG-2, a 22-kDa penta-EF-hand protein, is involved in cell death, signal transduction, membrane trafficking, etc., by interacting with various proteins in mammalian cells in a Ca²⁺-dependent manner. Most known ALG-2-interacting proteins contain proline-rich regions in which either PPYPXnYP (type 1 motif) or PXPGF (type 2 motif) is commonly found. Previous X-ray crystal structural analysis of the complex between ALG-2 and an ALIX peptide revealed that the peptide binds to the two hydrophobic pockets. In the present study, we resolved the crystal structure of the complex between ALG-2 and a peptide of Sec31A (outer shell component of coat complex II, COPII; containing the type 2 motif) and found that the peptide binds to the third hydrophobic pocket (Pocket 3). While amino acid substitution of Phe⁸⁵, a Pocket 3 residue, with Ala abrogated the interaction with Sec31A, it did not affect the interaction with ALIX. On the other hand, amino acid substitution of Tyr¹⁸⁰, a Pocket 1 residue, with Ala caused loss of binding to ALIX, but maintained binding to Sec31A. We conclude that ALG-2 recognizes two types of motifs at different hydrophobic surfaces. Furthermore, based on the results of serial mutational analysis of the ALG-2-binding sites in Sec31A, the type 2 motif was newly defined.