Multivalent lectin-carbohydrate interactions: Energetics and mechanisms of binding.

Lignin-based vitrimer containing dynamic borate ester bonds with intrinsic photoconversion and excellent photothermal remoldability

A dynamic binding mechanism allows the association of dumbbell-shaped ligand 2 with helical folded oligo(m-phenyleneethynylene)s 1 (see schematic representation). Association constants are oligomer length specific, with a maximum value for the icosamer and docosamer. These oligomers have helical conformations that are highly shape-complementary to 1; shorter and longer oligomers exhibit association constants roughly an order of magnitude smaller.

Workflow management systems, a relatively recent technology, are designed to make work more efficient, integrate heterogeneous application systems, and support inter-organizational processes in electronic commerce applications. This paper presents an infrastructure and a mechanism for achieving dynamic Inter-enterprise workflow management using e-services provided by collaborative e-business enterprises. E-services are distributed services that can be accessed programmatically on the Internet, using SOAP messages and the HTTP protocol. In this work, we categorize e-services according to their business types. E-service requests are specified in the activities of a process model according to some standardized e-service templates and are bound to the proper service providers at run-time by using a constraint-based, dynamic binding mechanism.

Contents: Preface. Part I: Oscillations in Single Neurons and Local Networks. G. Gross, J.M. Kowalski, B.K. Rhoades, Spontaneous and Evoked Oscillations in Cultured Mammalian Neuronal Networks. D.C. Tam, Detection of Oscillations and Synchronous Firing in Neurons. D.A. Baxter, H.A. Lechner, C.C. Canavier, R.J. Butera, Jr., A.A. DeFraneschi, J.W. Clark, Jr., J.H. Byrne, Coexisting Stable Oscillatory States in Single Cells and Multicellular Neuronal Oscillators. M. Stemmler, M. Usher, C. Koch, Oscillatory Local Field Potentials. G.J. Mpitsos, J.P. Edstrom, Computations Neurons Perform in Networks: Inside Versus Outside and Lessons Learned From a Sixteenth-Century Shoemaker. Part II: Oscillations in Cortical and Cortical/Subcortical Systems. I. Soltesz, The Interplay of Intrinsic and Synaptic Membrane Currents in Delta, Theta and 40-Hz Oscillations. E. Thomas, Dynamics of Low-Frequency Oscillations in a Model Thalamocortical Network. M.E. Jackson, L.J. Cauller, Towards the Function of Reciprocal Corticocortical Connections: Computational Modeling and Electrophysiological Studies. D. Young, An Oscillatory Model of Cortical Neural Processing. G.L. Yuen, Response Synchrony, APG Theory, and Motor Control. Part III: Oscillatory Models in Perception, Memory, and Cognition. D. Horn, I. Opher, Temporal Segmentation and Binding in Oscillatory Neural Systems. A. Grunewald, S. Grossberg, Perceptual Framing and Cortical Synchronization. D. DeMaris, Attention, Depth Gestalts, and Spatially Extended Chaos in the Perception of Ambiguous Figures. G. Borisyuk, R. Borisyuk, Y. Kazanovich, G. Strong, Oscillatory Neural Networks: Modeling Binding and Attention by Synchronization of Neural Activity. B. Baird, T. Troyer, F. Eeckman, Attentional Network Streams of Synchronized 40-Hz Activity in a Cortical Architecture of Coupled Oscillatory Associative Memories. Part IV: Applications of Synchronized and Chaotic Oscillations. G.E. Mobus, P.S. Fisher, Foraging Search at the Edge of Chaos. A.G. Brown, S. Collins, An Oscillatory Associative Memory Analogue Architecture. N.S. Park, D. Robertson, K. Stenning, Symbolic Knowledge Encoding Using a Dynamic Binding Mechanism and an Embedded Inference Mechanism. A. Jagota, X. Wang, Oscillations in Discrete and Continuous Hopfield Networks. S. Wolpert, Modeling Neural Oscillation Using VLSI-Based Neuromimes.

This chapter describes how synchronous activity between neuron elements can be used to build a dynamic binding mechanism and knowledge encoding mechanisms in a connectionist manner. The purpose of these mechanisms is to build a connectionist inference architecture that can replicate common symbolic styles of inference. To build such an inference architecture, an extended temporal synchrony approach (Park, Robertson, & Stenning, 1995) is used as a basic building block. This is a revision and extension of an approach to the dynamic binding problem in connectionist systems, proposed by Shastri and Ajjanagadde (1993). In addition, we introduce a set of algorithms that gives us a means of compiling a class of symbolic rules into a uniform inference network called a structured predicate network. This is used as a connectionist knowledge encoding mechanism which encodes symbolic rules and supports very fast inference.

Intrinsically disordered protein domains often have multiple binding partners. It is plausible that the strength of pairing with specific partners evolves from an initial low affinity to a higher affinity. However, little is known about the molecular changes in the binding mechanism that would facilitate such a transition. We previously showed that the interaction between two intrinsically disordered domains, NCBD and CID, likely emerged in an ancestral deuterostome organism as a low-affinity interaction that subsequently evolved into a higher-affinity interaction before the radiation of modern vertebrate groups. Here we map native contacts in the transition states of the low-affinity ancestral and high-affinity human NCBD/CID interactions. We show that the coupled binding and folding mechanism is overall similar but with a higher degree of native hydrophobic contact formation in the transition state of the ancestral complex and more heterogeneous transient interactions, including electrostatic pairings, and an increased disorder for the human complex. Adaptation to new binding partners may be facilitated by this ability to exploit multiple alternative transient interactions while retaining the overall binding and folding pathway.

A soluble lectin which agglutinates trypsin-treated rabbit erythrocytes was purified from calf heart using affinity chromatography on asialofetuin-Sepharose. Its molecular weight was determined by gel filtration to be approximately 17,000. On polyacrylamide gel electrophoresis in sodium dodecyl sulfate, the predominant molecular species had a molecular weight of 9,000, suggesting that the lectin is a dimer. Binding studies performed with iodinated lectin revealed that neuraminidase-treated calf erythrocytes contained approximately 5 X 10(6) lectin binding sites per cell. Native calf and rabbit erythrocytes bound the lectin, but human and rat erythrocytes required neuraminidase and trypsin treatment, respectively, for lectin binding to occur. A number of saccharides, glycopeptides, and glycoproteins possess haptene inhibitory activity toward lectin binding to erythrocytes. The most potent of these have either galactose beta leads to galactose beta leads to, galactose beta N-acetylglucosamine beta leads to, or galactose beta leads to N-acetylglucosamine beta leads to sequences at their nonreducing termini. Lactose and galactose beta 1 leads to 3N-acetylgalactosamine are the next best haptenes. Finally, alpha-linked galactose residues and free galactose are very weak haptenes. The presences of a terminal sialic acid residue impairs haptene activity in all instances. Calf heart also contains a membrane-associated lectin which is very similar but not identical with the soluble lectin. A soluble beta-galactoside binding lectin was also isolated from calf lung. It has the same molecular size and subunit structure as the soluble heart lectin and is antigenically identical. In binding studies, the pattern of inhibition by various haptenes was the same for all three lectins.

As the global marketplace becomes more and more competitive, business organisations often need to team up and operate as a virtual enterprise to utilise the best of their resources for achieving their common business goals. As the business environment of a virtual enterprise is highly dynamic, it is necessary to develop a workflow management technology that is capable of handling dynamic workflows across enterprise boundaries. This paper describes a Dynamic Workflow Model (DWM) and a dynamic workflow management system (DynaFlow) for modelling and controlling the execution of inter-organisational business processes. DWM enables the specification of dynamic properties associated with a business process model. It extends the underlying model of the WfMC's WPDL by adding connectors, events, triggers and rules as its modelling constructs. It also encapsulates activity definitions and allows web service (or e-service) requests to be included as a part of the activity specification. Using DWM as the underlying model, DynaFlow makes use of an Event-Trigger-Rule (ETR) server to trigger rules during the enactment of a workflow process to enforce business rules and policies and/or to modify the process model at run-time. A constraint-based, dynamic service binding mechanism is used to dynamically bind web service requests to web services that satisfy the requirements of the requests.

Colony-stimulating factor (CSF-1) activates several members belonging to the STAT (signal transducers and activators of transcription) family of transcription factors. We investigated the DNA binding complexes activated by CSF-1 in several cell lines and compared them with complexes activated by platelet-derived growth factor and interleukin 3. Our results indicate that the SIF-A complex activated by CSF-1 and platelet-derived growth factor may contain STAT3/STAT5 heterodimers binding to the high affinity SIF binding site, m67. In addition, both growth factors activate one or several STAT5-containing protein complexes binding to the prolactin-inducible element, PIE. The formation of these complexes was cell type and growth factor specific. Interleukin 3 activated only PIE binding complexes containing STAT5A and STAT5B and did not activate m67 binding complexes. It appears, therefore, that STAT5 cannot bind to m67 as a homodimer, but it can bind if it is dimerized with STAT3, whereas it can bind to the PIE element without being either complexed with STAT3 or any other known STAT protein, possibly as a homodimer or as STAT5A/STAT5B heterodimer. However, in addition, STAT5 may heterodimerize with other proteins and form novel PIE binding complexes.

Carbohydrate-binding proteins, also known as lectins, play a key role in pathogen infection, cell-cell communication, and immune regulation. They recognize pathogen surface–specific glycan patterns via their multiple glycan-binding domains and exploit multivalency to enhance binding affinity and impose specificity. As a result, designing glycoconjugates to specifically block pathogen binding to target lectins is an attractive strategy for preventing infection. However, the crystal structures of some key lectins remain unavailable, making it difficult to design glycoconjugates that can match the target lectin binding site arrangement in order to differentiate between lectins with overlapping glycan specificity. This differentiation would be necessary in order to provide potent and highly specific targeting. A good example of this is observed for a pair of closely related and functionally different tetrameric lectins: DC-SIGN and DC-SIGNR. These lectins play a key role in HIV and Ebola virus infection, yet their detailed structural information remains unknown. Herein we show that fluorescent quantum dots displaying a dense layer of polyvalent glycans are powerful multifunctional probes for multivalent lectin-glycan interactions. They can not only provide important structural information on a lectin's binding site orientation and binding mode, but they also act as potent inhibitors against lectin-mediated virus infection.

Carbohydrate-binding proteins, lectins, are the main binding partners of tumor-associated carbohydrate antigens (TACAs) on the cell surface. Interactions between the tumor-associated carbohydrate antigens of Mucin 1 (TA MUC1) and the carbohydrate-binding proteins, lectins, often lead to the creation of a pro-tumor microenvironment favoring tumor initiation, progression, metastasis, and immune evasion. Macrophage galactose binding lectin (MGL) is a C-type lectin receptor found on antigen-presenting cells that facilitates the uptake of carbohydrate antigens for antigen presentation, modulating the immune response homeostasis, autoimmunity, and cancer. MGL has been identified as a receptor of Thomsen-nouvelle (Tn, CD175) and sialylated Tn (sialyl-Tn, CD175s) antigens. The interaction between Tn and sialyl-Tn antigens of tumor-associated MUC1 and hMGL likely plays a critical role in establishing the immunological tolerance to tumor cells. Yet, MGL targeting is an attractive approach to enhance cancer vaccine efficacy. The ability of hMGL to regulate immune response by engaging tumor-associated MUC1 to either augment the anti-tumorigenic effects or minimize the pro-tumorigenic effects is poorly understood. Thus, a thorough understanding of their binding interaction is essential for it to be exploited for cancer vaccine strategies. The synthesis of MUC1 glycopeptide models carrying a single or multiple Tn and/or sialyl-Tn antigen(s) is described. A novel approach for the sialyl-Tn threonine building block suitable for the solid phase peptide synthesis was developed. The thermodynamic profile of the binding interaction between the human MGL and MUC1 glycopeptide models was analyzed using isothermal titration calorimetry. All studied interactions, regardless of the glycan’s site of attachment or density, exhibited enthalpy-driven thermodynamics. The thermodynamic analysis pointed out the critical role of entropy in driving the affinity enhancement of multivalent interactions. Further studies into the nature of the hMGL ligands and their role in shaping the immune responses are warranted. Citation Format: Mare Cudic, Ramya Ayyalasomayajula, Ivet Boneva, Donella M. Beckwith, Sabine André, Herbert Kaltner. Targeting macrophage galactose binding lectin-tumor associated MUC1 immune axis in cancer [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A012.

FcγRs play a critical role in the immune response following recognition of invading particles and tumor associated antigens by circulating antibodies. In the present study we investigated the role of FcγR glycosylation in the IgG interaction and observed a stabilizing role for receptor N-glycans. We performed a complete glycan analysis of the recombinant FcγRs (FcγRIa, FcγRIIa, FcγRIIb, FcγRIIIa(Phe158/Val158), and FcγRIIIb) expressed in human cells and demonstrate that receptor glycosylation is complex and varied between receptors. We used surface plasmon resonance to establish binding patterns between rituximab and all receptors. Complex binding was observed for FcγRIa and FcγRIIIa. The IgG-FcγR interaction was further investigated using a combination of kinetic experiments and enzymatically deglycosylated FcγRIa and FcγRIIIa(Phe158/Val158) receptors in an attempt to determine the underlying binding mechanism. We observed that antibody binding levels decreased for deglycosylated receptors, and at the same time, binding kinetics were altered and showed a more rapid approach to steady state, followed by an increase in the antibody dissociation rate. Binding of rituximab to deglycosylated FcγRIIIa(Phe158) was now consistent with a 1:1 binding mechanism, while binding of rituximab to FcγRIIIa(Val158) remained heterogeneous. Kinetic data support a complex binding mechanism, involving heterogeneity in both antibody and receptor, where fucosylated and afucosylated antibody forms compete in receptor binding and in receptor molecules where heterogeneity in receptor glycosylation plays an important role. The exact nature of receptor glycans involved in IgG binding remains unclear and determination of rate and affinity constants are challenging. Here, the use of more extended competition experiments appear promising and suggest that it may be possible to determine dissociation rate constants for high affinity afucosylated antibodies without the need to purify or express such variants. The data described provide further insight into the complexity of the IgG-FcγR interaction and the influence of FcγR glycosylation.

Gli3/Spop Multivalent Interactions are Concentration-Dependent

Influenza viruses are a major public health threat worldwide. The influenza hemagglutinin (HA) plays an essential role in the virus life cycle. Due to the high conservation of the HA stem region, it has become an especially attractive target for inhibitors for therapeutics. In this study, molecular simulation was applied to study the mechanism of a small molecule inhibitor (MBX2329) of influenza HA. Behaviors of the small molecule under neutral and acidic conditions were investigated, and an interesting dynamic binding mechanism was found. The results suggested that the binding of the inhibitor with HA under neutral conditions facilitates only its intake, while it interacts with HA under acidic conditions using a different mechanism at a new binding site. After a series of experiments, we believe that binding of the inhibitor can prevent the release of HA1 from HA2, further maintaining the rigidity of the HA2 loop and stabilizing the distance between the long helix and short helices. The investigated residues in the new binding site show high conservation, implying that the new binding pocket has the potential to be an effective drug target. The results of this study will provide a theoretical basis for the mechanism of new influenza virus inhibitors.

Review for "Molecular Insights into Nilvadipine-Hemoglobin Interactions: Conformational Dynamics and Binding Mechanisms"