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1.
Gufeng Xu Maikun Teng Liwen Niu Peng Liu Yuhui Dong Qun Liu Qingqiu Huang Quan Hao 《Acta Crystallographica. Section D, Structural Biology》2004,60(11):2035-2037
Aall‐A and Aall‐B, two novel heterodimeric snake‐venom C‐type lectin‐like proteins (sv‐CLPs), were purified from the venom of Deinagkistrodon acutus from Anhui, China. Strikingly, both these proteins can localize on and congregate human erythrocytes, instead of aiming at the common targets of sv‐CLPs such as platelet glycoproteins, von Willebrand factors, coagulant factors etc. The crystals of Aall‐A belong to space group P2, with unit‐cell parameters a = 105.2, b = 56.2, c = 108.7 Å, β = 100.5°, and diffract to 2.0 Å resolution, while the crystals of Aall‐B belong to space group P212121, with unit‐cell parameters a = 36.8, b = 56.5, c = 149.2 Å, and diffract to 2.2 Å resolution. To our knowledge, this is the first report of sv‐CLPs with this unique function and of their preliminary crystallographic analysis. 相似文献
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C‐type lectins (CTLs) play a variety of roles in plants and animals. They are involved in animal development, pathogen recognition, and the activation of immune responses. CTLs carry one or more non‐catalytic carbohydrate‐recognition domains (CRDs) to bind specific carbohydrates reversibly. Here, we report the molecular cloning and functional analysis of a single‐CRD CTL, named C‐type lectin‐S2 (BmCTL‐S2) from the domesticated silkmoth Bombyx mori (Lepidoptera: Bombycidae). The ORF of CTL‐S2 is 666 bp, which encodes a putative protein of 221 amino acids. BmCTL‐S2 is expressed in a variety of immune‐related tissues, including hemocytes and fat body among others. BmCTL‐S2 mRNA level in the midgut and the fat body was significantly increased by bacterial challenges. The recombinant protein (rBmCTL‐S2) bound different bacterial cell wall components and bacterial cells. rBmCTL‐S2 also inhibited the growth of Bacillus subtilis and Staphylococcus aureus. Taken together, we infer that BmCTL‐S2 is a pattern‐recognition receptor with antibacterial activities. 相似文献
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Sijiu Liu Zhongliang Zhu Jinpeng Sun Zhiqiang Zhu Qingqiu Huang Maikun Teng Liwen Niu 《Acta Crystallographica. Section D, Structural Biology》2002,58(4):675-678
A snake‐venom C‐type lectin‐like protein, agkaggregin, has been isolated from Agkistrodon acutus venom. Agkaggregin has an apparent molecular mass of about 28 kDa and consists of two different types of subunits, an α‐subunit (∼15 kDa) and a β‐subunit (∼14 kDa). Agkaggregin has the ability to induce platelet aggregation at concentrations of the order of nanomoles. The agkaggregin crystals grew for nearly a year by hanging‐drop vapour diffusion and belong to the I222 space group, with unit‐cell parameters a = 64.75, b = 74.21, c = 133.24 Å. One asymmetric unit contains one αβ heterodimer, corresponding to a volume‐to‐mass ratio of 2.795 Å3 Da−1. Agkaggregin may exist in two association forms: an αβ heterodimer and a dimer of αβ heterodimers that associates during the long process of crystallization. 相似文献
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Bettina Bryde Nielsen Jette Sandholm Kastrup Hanne Rasmussen Jonas Heilskov Graversen Michael Etzerodt Hans Christian Thgersen Ingrid Kjller Larsen 《Acta Crystallographica. Section D, Structural Biology》2000,56(5):637-639
The two C‐terminal domains, TN23 (residues 17–181), of human recombinant tetranectin, a plasminogen kringle 4 binding C‐type lectin, have been crystallized in two different space groups. Using PEG 8000 as precipitant and at a pH of 8.5, crystals belonging to the monoclinic space group C2 are obtained, with unit‐cell parameters a = 160.4, b = 44.7, c = 107.5 Å, β = 127.6°. Using sodium formate as precipitant and at a pH of 5.0, TN23 crystallizes in a rhombohedral space group, with unit‐cell parameters a = b = c = 107.4 Å, α = β = γ = 78.3°. A full data set to 4.5 Å has been collected from the monoclinic crystals. Using the structure of full‐length tetranectin, a molecular‐replacement solution has been obtained. The crystal packing shows that TN23 crystallizes as a trimer, with one trimer in the asymmetric unit. 相似文献
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Malgorzata E. Mnich Rob van Dalen David Gerlach Astrid Hendriks Guoqing Xia Andreas Peschel Jos A.G. van Strijp Nina M. van Sorge 《Cellular microbiology》2019,21(10)
Staphylococcus aureus is a common skin commensal but is also associated with various skin and soft tissue pathologies. Upon invasion, S. aureus is detected by resident innate immune cells through pattern‐recognition receptors (PRRs), although a comprehensive understanding of the specific molecular interactions is lacking. Recently, we demonstrated that the PRR langerin (CD207) on epidermal Langerhans cells senses the conserved β‐1,4‐linked N‐acetylglucosamine (GlcNAc) modification on S. aureus wall teichoic acid (WTA), thereby increasing skin inflammation. Interestingly, the S. aureus ST395 lineage as well as certain species of coagulase‐negative staphylococci (CoNS) produce a structurally different WTA molecule, consisting of poly‐glycerolphosphate with α‐O‐N‐acetylgalactosamine (GalNAc) residues, which are attached by the glycosyltransferase TagN. Here, we demonstrate that S. aureus ST395 strains interact with the human Macrophage galactose‐type lectin (MGL; CD301) receptor, which is expressed by dendritic cells and macrophages in the dermis. MGL bound S. aureus ST395 in a tagN‐ and GalNAc‐dependent manner but did not interact with different tagN‐positive CoNS species. However, heterologous expression of Staphylococcus lugdunensis tagN in S. aureus conferred phage infection and MGL binding, confirming the role of this CoNS enzyme as GalNAc‐transferase. Functionally, the detection of GalNAc on S. aureus ST395 WTA by human monocyte‐derived dendritic cells significantly enhanced cytokine production. Together, our findings highlight differential recognition of S. aureus glycoprofiles by specific human innate receptors, which may affect downstream adaptive immune responses and pathogen clearance. 相似文献
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Veronika Krej
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ov Ji&#x;í Brynda 《Acta Crystallographica. Section D, Structural Biology》2011,67(3):204-211
Galectin‐4, a member of the tandem‐repeat subfamily of galectins, participates in cell‐membrane interactions and plays an important role in cell adhesion and modulation of immunity and malignity. The oligosaccharide specificity of the mouse galectin‐4 carbohydrate‐recognition domains (CRDs) has been reported previously. In this work, the structure and binding properties of the N‐terminal domain CRD1 were further investigated and the crystal structure of CRD1 in complex with lactose was determined at 2.1 Å resolution. The lactose‐binding affinity was characterized by fluorescence measurements and two lactose‐binding sites were identified: a high‐affinity site with a Kd value in the micromolar range (Kd1 = 600 ± 70 µM) and a low‐affinity site with Kd2 = 28 ± 10 mM. 相似文献
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Zhang XW Wang XW Sun C Zhao XF Wang JX 《Archives of insect biochemistry and physiology》2011,76(3):168-184
Lectins are potential immune recognition proteins. In this study, a novel C-type lectin (Pc-Lec1) is reported in freshwater crayfish Procambarus clarkii. Pc-Lec1 encodes a protein of 163 amino acids with a putative signal peptide and a single carbohydrate recognition domain. It was constitutively expressed in various tissues of a normal crayfish, especially in the hepatopancreas and gills. Expressions of Pc-Lec1 were up-regulated in the hepatopancreas and gills of crayfish challenged with Vibrio anguillarum, Staphylococcus aureus, or the white spot syndrome virus. Recombinant mature Pc-Lec1 bound bacteria and polysaccharides (peptidoglycan, lipoteichoic acid, and lipopolysaccharide) but did not agglutinate bacteria. Pc-Lec1 enhanced hemocyte encapsulation of the sepharose beads in vitro, and the blocking of beads by a polyclonal antibody inhibited encapsulation. Pc-Lec1 promoted clearance of V. anguillarum in vivo. These results suggest that Pc-Lec1 is a pattern recognition receptor and participates in cellular immune response. Pc-Lec1 performs its function as an opsonin by enhancing the encapsulation or clearance of pathogenic bacteria. 相似文献
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Srikanth K Park J Stanley DW Kim Y 《Archives of insect biochemistry and physiology》2011,78(3):145-160
Hemocyte-spreading behavior is required for expressing a cellular immune response, nodulation, which clears the vast majority of invading microbes from circulation. The nodulation response is completed by a layer of plasmatocytes, which spread over the nodule and initiate a malanization process leading to darkened nodules. Plasmatocyte-spreading peptide (PSP), the first reported insect cytokine, is responsible for mediating the spreading and attachment of some subclasses of plasmatocytes to nodules. Prostaglandins (PGs), one group of eicosanoids formed from arachidonic acid (AA), also mediate plasmatocyte spreading (PS), although the potential interactions between the PSP and PG signal transduction pathways have not been investigated. We tested our hypothesis that PSP acts via biosynthesis of eicosanoids, specifically PGs, in the beet armyworm, Spodoptera exigua. In this study, we report that (1) PSP and PGE(2) independently stimulated Ca(++)-dependent PS, (2) inhibitors of PG biosynthesis reversibly blocked PS, (3) dsRNA silencing the gene encoding proPSP blocked PS, which was rescued by PSP and by AA, (4) PSP-stimulated PS was reversibly impaired by inhibitors of PG biosynthesis, and (5) the inhibitor-impaired spreading was rescued by AA. Taken together, these points strongly support our model showing that PSP acts via a plasmatocyte-surface receptor, which stimulates biosynthesis of the PGs responsible for mediating plasmatocytes spreading. 相似文献
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Lei Zhang Joseph A. Ringbauer Jr. Cynthia l. Goodman Tamra Reall Xing‐Fu Jiang David Stanley 《Archives of insect biochemistry and physiology》2018,97(4)
Insect immunity includes a surveillance system that detects and signals infections, coupled with hemocytic and humoral immune functions. These functions are signaled and coordinated by several biochemicals, including biogenic amines, insect cytokines, peptides, and prostaglandins (PGs). The actions of these mediators are coordinated within cells by various forms of cross‐talk among the signaling systems and they result in effective reactions to infection. While this is well understood, we lack information on how immune‐mediated recovery influences subsequent juvenile development in surviving insects. We investigated this point by posing the hypothesis that PG signaling is necessary for larval recovery, although the recovery imposes biological costs, registered in developmental delays and failures in surviving individuals. Here, we report that nodulation responses to infections by the bacterium, Serratia marcescens, increased over time up to 5 h postinfection, with no further nodulation; it increased in a linear manner with increasing bacterial dosages. Larval survivorship decreased with increasing bacterial doses. Treating larvae with the PG‐biosynthesis inhibitor, indomethacin, led to sharply decreased nodulation reactions to infection, which were rescued in larvae cotreated with indomethacin and the PG‐precursor, arachidonic acid. Although nodulation was fully rescued, all bacterial challenged larvae suffered reduced survivorship compared to controls. Bacterial infection led to reduced developmental rates in larvae, but not pupae. Adult emergence from pupae that developed from experimental larvae was also decreased. Taken together, our data potently bolster our hypothesis. 相似文献
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Hideaki Unno Shuhei Higuchi Shuichiro Goda Tomomitsu Hatakeyama 《Acta Crystallographica. Section F, Structural Biology Communications》2020,76(6):271-277
The C‐type lectins SPL‐1 and SPL‐2 from the bivalve Saxidomus purpuratus are composed of A and B chains and of two B chains, respectively. They bind specific carbohydrates containing acetamido groups, such as N‐acetylglucosamine (GlcNAc) and N‐acetylgalactosamine (GalNAc), in a Ca2+‐independent manner. Unlike ordinary C‐type lectins, which require Ca2+ ions for carbohydrate recognition, these lectins recognize specific carbohydrates mainly through interactions with the acetamido group without Ca2+ ions, even though Ca2+ enhances the binding affinity of these lectins, especially SPL‐1. In the present study, the crystal structure of the SPL‐1–GlcNAc complex in the presence of Ca2+ revealed that the binding of SPL‐1 to GlcNAc is stabilized by hydrogen bonds to the water molecule(s) coordinating Ca2+, whereas in ordinary C‐type lectins Ca2+ directly forms coordinate bonds to the hydroxy groups of carbohydrates. These differences may also allow SPL‐1 and SPL‐2 to recognize both GlcNAc and GalNAc, which have different orientations of the 4‐hydroxy group. 相似文献
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Puneet Juneja Ashit Rao Helmut Clfen Kay Diederichs Wolfram Welte 《Acta Crystallographica. Section F, Structural Biology Communications》2014,70(2):260-262
Sea urchin spicules have a calcitic mesocrystalline architecture that is closely associated with a matrix of proteins and amorphous minerals. The mechanism underlying spicule formation involves complex processes encompassing spatio‐temporally regulated organic–inorganic interactions. C‐type lectin domains are present in several spicule matrix proteins in Strongylocentrotus purpuratus, implying their role in spiculogenesis. In this study, the C‐type lectin domain of SM50 was overexpressed, purified and crystallized using a vapour‐diffusion method. The crystal diffracted to a resolution of 2.85 Å and belonged to space group P212121, with unit‐cell parameters a = 100.6, b = 115.4, c = 130.6 Å, α = β = γ = 90°. Assuming 50% solvent content, six chains are expected to be present in the asymmetric unit. 相似文献
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Jzsef Dob Veronika Harmat Edina Sebestyn Lszl Beinrohr Pter Zvodszky Pter Gl 《Acta Crystallographica. Section F, Structural Biology Communications》2008,64(9):781-784
MASP‐1, a multidomain serine protease, is a component of the lectin pathway of complement. Its precise function is unknown, although it seems to enhance the complement‐activating capacity of MASP‐2, a related enzyme. MASP‐1 has also been implicated as playing a role in blood coagulation. It is mostly found associated with mannose‐binding lectin (MBL) and ficolins. Early attempts to crystallize MASP‐1 failed because of the inhomogeneity of the purified material. MASP‐1 was shown by acidic nondenaturing PAGE to be composed of differently charged species, which are most likely to be the products of deamidation occurring during the refolding procedure. Sequential cation‐exchange and anion‐exchange chromatography resulted in a homogeneous material, which was successfully crystallized. The best crystal diffracted to 2.55 Å resolution and belonged to space group P212121, with unit‐cell parameters a = 68.4, b = 70.4, c = 121.4 Å. The crystal structure of MASP‐1 may help in understanding the function of this mysterious serine protease. 相似文献
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Masahiro Fujihashi Diane H. Peapus Eijiro Nakajima Tsuyoshi Yamada Jun‐ichi Saito Akiko Kita Yoshiki Higuchi Yoko Sugawara Akikazu Ando Nobuo Kamiya Yoshiho Nagata Kunio Miki 《Acta Crystallographica. Section D, Structural Biology》2003,59(2):378-380
A fucose‐specific lectin from Aleuria aurantia was crystallized in its native form and was also cocrystallized with HgCl2. Crystallization was performed using the sitting‐drop vapour‐diffusion method with ammonium sulfate as a precipitant. Both the Hg‐free native crystals and the Hg cocrystals belong to the hexagonal space group P6522. The unit‐cell parameters for the Hg‐free form are a = 84.0, c = 250.1 Å and for the Hg cocrystals are a = 83.9, c = 254.3 Å. Both forms of the crystals diffract X‐rays to 2.3 Å resolution and are suitable for high‐resolution crystal structure determination. Initial phasing was successfully performed by the MAD method using the Hg cocrystals and the electron density obtained was good enough for model building. 相似文献
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Ivan Tattoli Matthew T Sorbara Chloe Yang Sharon A Tooze Dana J Philpott Stephen E Girardin 《The EMBO journal》2013,32(23):3066-3078
Listeria can escape host autophagy defense pathways through mechanisms that remain poorly understood. We show here that in epithelial cells, Listeriolysin (LLO)‐dependent cytosolic escape of Listeria triggered a transient amino‐acid starvation host response characterized by GCN2 phosphorylation, ATF3 induction and mTOR inhibition, the latter favouring a pro‐autophagic cellular environment. Surprisingly, rapid recovery of mTOR signalling was neither sufficient nor necessary for Listeria avoidance of autophagic targeting. Instead, we observed that Listeria phospholipases PlcA and PlcB reduced autophagic flux and phosphatidylinositol 3‐phosphate (PI3P) levels, causing pre‐autophagosomal structure stalling and preventing efficient targeting of cytosolic bacteria. In co‐infection experiments, wild‐type Listeria protected PlcA/B‐deficient bacteria from autophagy‐mediated clearance. Thus, our results uncover a critical role for Listeria phospholipases C in the inhibition of autophagic flux, favouring bacterial escape from host autophagic defense. 相似文献