Pathogenesis ofCampylobacter fetusInfections: Critical Role of High-Molecular- Weight S-Layer Proteins in Virulence

Abstract This investigation has provided insight into the critical role of solution properties on the course of cationic polymerization and has led to a technique for reconciling the opposing demands for synthesis of isoolefin-diene copolymers both free from gel and high in molecular weight. By this technique, the synthesis of a broad range of intermediate-unsaturation elastomers of quality has been realized.

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Surface activation of factor XII (Hageman factor) — Critical role of high molecular weight kininogen and another potentiator

Agents and Actions ◽

10.1007/bf01972404 ◽

1978 ◽

Vol 8 (1-2) ◽

pp. 65-72 ◽

Cited By ~ 9

Author(s):

J. Y. C. Chan ◽

C. E. Burrowes ◽

H. Z. Movat

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Critical Role ◽

Surface Activation ◽

Factor Xii ◽

High Molecular Weight Kininogen ◽

Hageman Factor

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Role of arginine residues in the coagulant activity of high molecular weight kininogen

Blood ◽

10.1182/blood.v67.3.805.bloodjournal673805 ◽

1986 ◽

Vol 67 (3) ◽

pp. 805-810

Author(s):

JJ Chang ◽

CF Scott ◽

RW Colman

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Critical Role ◽

Cleavage Sites ◽

High Molecular Weight Kininogen ◽

Coagulant Activity ◽

Factor Xiia ◽

Arginine Residues ◽

Arginine Modification

High molecular weight (HMW) kininogen, the cofactor for activation of the contact system of plasma proteolysis, transports and optimally positions prekallikrein and factor XI on a negatively charged surface, allowing those zymogens to be activated by surface-bound factor XIIa. HMW kininogen circulates in plasma as a procofactor that, after cleavage by kallikrein or factor XIIa, gains ability to bind to the surface. The mechanism responsible for this increased affinity for the surface is unknown. We hypothesized that modification of arginine residues may prevent cleavage of HMW kininogen, since the initial kallikrein-induced cleavage sites on the HMW kininogen molecule are at the NH2 terminal and the COOH terminal of the bradykinin-containing portion of the molecule, each of which contains arginine. We found that modification with butanedione of four arginine residues in the HMW kininogen molecule prevented bradykinin release, which results from cleavage of HMW kininogen. Furthermore, HMW kininogen coagulant activity was lost, in proportion to the degree of arginine modification, until 6.6 residues had been modified. Complex formation with prekallikrein, however, was found to be uneffected by the modification of modified HMW kininogen. To account for the loss of coagulant activity, we also examined the ability of modified HMWKa (active cofactor) to bind to an activating surface. The affinity of modified HMWKa for kaolin was tenfold less than the affinity of unmodified HMWKa. These data suggest that arginine residues play a critical role in the ability of HMW kininogen to function as an activation cofactor, both by preventing the cleavages that produce HMWKa as well as by decreasing the affinity of HMWKa for the surface.

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Role of arginine residues in the coagulant activity of high molecular weight kininogen

Blood ◽

10.1182/blood.v67.3.805.805 ◽

1986 ◽

Vol 67 (3) ◽

pp. 805-810 ◽

Cited By ~ 2

Author(s):

JJ Chang ◽

CF Scott ◽

RW Colman

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Critical Role ◽

Cleavage Sites ◽

High Molecular Weight Kininogen ◽

Coagulant Activity ◽

Factor Xiia ◽

Arginine Residues ◽

Arginine Modification

Abstract High molecular weight (HMW) kininogen, the cofactor for activation of the contact system of plasma proteolysis, transports and optimally positions prekallikrein and factor XI on a negatively charged surface, allowing those zymogens to be activated by surface-bound factor XIIa. HMW kininogen circulates in plasma as a procofactor that, after cleavage by kallikrein or factor XIIa, gains ability to bind to the surface. The mechanism responsible for this increased affinity for the surface is unknown. We hypothesized that modification of arginine residues may prevent cleavage of HMW kininogen, since the initial kallikrein-induced cleavage sites on the HMW kininogen molecule are at the NH2 terminal and the COOH terminal of the bradykinin-containing portion of the molecule, each of which contains arginine. We found that modification with butanedione of four arginine residues in the HMW kininogen molecule prevented bradykinin release, which results from cleavage of HMW kininogen. Furthermore, HMW kininogen coagulant activity was lost, in proportion to the degree of arginine modification, until 6.6 residues had been modified. Complex formation with prekallikrein, however, was found to be uneffected by the modification of modified HMW kininogen. To account for the loss of coagulant activity, we also examined the ability of modified HMWKa (active cofactor) to bind to an activating surface. The affinity of modified HMWKa for kaolin was tenfold less than the affinity of unmodified HMWKa. These data suggest that arginine residues play a critical role in the ability of HMW kininogen to function as an activation cofactor, both by preventing the cleavages that produce HMWKa as well as by decreasing the affinity of HMWKa for the surface.

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The Role of High Molecular Weight Kininogen and Prothrombin as Cofactors in the Binding of Factor XI A3 Domain to the Platelet Surface

Journal of Biological Chemistry ◽

10.1074/jbc.m001890200 ◽

2000 ◽

Vol 275 (33) ◽

pp. 25139-25145 ◽

Cited By ~ 30

Author(s):

David H. Ho ◽

Karen Badellino ◽

Frank A. Baglia ◽

Mao-Fu Sun ◽

Ming-Ming Zhao ◽

...

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

High Molecular Weight Kininogen ◽

Factor Xi ◽

Platelet Surface

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Role of Sintering Temperature in Production of Nepheline Ceramics-Based Geopolymer with Addition of Ultra-High Molecular Weight Polyethylene

Materials ◽

10.3390/ma14051077 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1077

Author(s):

Romisuhani Ahmad ◽

Mohd Mustafa Al Bakri Abdullah ◽

Wan Mastura Wan Ibrahim ◽

Kamarudin Hussin ◽

Fakhryna Hannanee Ahmad Zaidi ◽

...

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Sintering Temperature ◽

Ceramic Materials ◽

Microstructural Properties ◽

Sintering Process ◽

Final Microstructure ◽

Change Of Microstructure ◽

Ultra High Molecular Weight

The primary motivation of developing ceramic materials using geopolymer method is to minimize the reliance on high sintering temperatures. The ultra-high molecular weight polyethylene (UHMWPE) was added as binder and reinforces the nepheline ceramics based geopolymer. The samples were sintered at 900 °C, 1000 °C, 1100 °C, and 1200 °C to elucidate the influence of sintering on the physical and microstructural properties. The results indicated that a maximum flexural strength of 92 MPa is attainable once the samples are used to be sintered at 1200 °C. It was also determined that the density, porosity, volumetric shrinkage, and water absorption of the samples also affected by the sintering due to the change of microstructure and crystallinity. The IR spectra reveal that the band at around 1400 cm−1 becomes weak, indicating that sodium carbonate decomposed and began to react with the silica and alumina released from gels to form nepheline phases. The sintering process influence in the development of the final microstructure thus improving the properties of the ceramic materials.

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Derivation of the material models for ultra-high molecular-weight polyethylene fiber-reinforced armor-grade composites with different architectures

Engineering Computations ◽

10.1108/ec-05-2015-0120 ◽

2016 ◽

Vol 33 (3) ◽

Cited By ~ 1

Author(s):

Mica Grujicic ◽

Jennifer Snipes ◽

S. Ramaswami ◽

Vasudeva Avuthu ◽

Chian-Fong Yen ◽

...

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Design Methodology ◽

Critical Role ◽

Fiber Reinforcement ◽

Mechanical Tests ◽

Transverse Impact ◽

Material Models ◽

Polyethylene Fiber ◽

Ultra High Molecular Weight

Purpose To overcome the problem of inferior through-the-thickness mechanical properties displayed by armor-grade composites based on 2-D reinforcement architectures, armor-grade composites based on 3D fiber-reinforcement architectures have recently been investigated experimentally. Design/methodology/approach The subject of the present work is armor-grade composite materials reinforced using ultra-high-molecular-weight polyethylene fibers and having four (two 2D and two 3D) prototypical architectures, as well as the derivation of the corresponding material models. The effect of the reinforcement architecture is accounted for by constructing the appropriate unit cells (within which the constituent materials and their morphologies are represented explicitly) and subjecting them to a series of virtual mechanical tests. The results obtained are used within a post-processing analysis to derive and parameterize the corresponding homogenized-material models. One of these models (specifically, the one for 0°/90° cross-collimated fiber architecture) was directly validated by comparing its predictions with the experimental counterparts. The other models are validated by examining their physical soundness and details of their predictions. Lastly, the models are integrated as user-material subroutines, and linked with a commercial finite-element package, in order to carry out a transient non-linear dynamics analysis of ballistic transverse impact of armor-grade composite-material panels with different reinforcement architectures. Findings It is found that the reinforcement architecture plays a critical role in the overall ballistic limit of the armor panel, as well as in its structural and damage/failure response. Originality/value To the authors’ knowledge, the present work is the first reported attempt to assess, computationally, the utility and effectiveness of 3D fiber-reinforcement architectures for ballistic impact applications.

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Actinobacteria challenge the paradigm: A unique protein architecture for a well-known, central metabolic complex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2112107118 ◽

2021 ◽

Vol 118 (48) ◽

pp. e2112107118

Author(s):

Eduardo M. Bruch ◽

Pierre Vilela ◽

Lu Yang ◽

Alexandra Boyko ◽

Norik Lexa-Sapart ◽

...

Keyword(s):

Molecular Weight ◽

Metabolic Engineering ◽

High Molecular Weight ◽

Protein Oligomerization ◽

Central Metabolism ◽

Hollow Core ◽

Protein Architecture ◽

Unique Protein ◽

Gene Coding

α-oxoacid dehydrogenase complexes are large, tripartite enzymatic machineries carrying out key reactions in central metabolism. Extremely conserved across the tree of life, they have been, so far, all considered to be structured around a high–molecular weight hollow core, consisting of up to 60 subunits of the acyltransferase component. We provide here evidence that Actinobacteria break the rule by possessing an acetyltranferase component reduced to its minimally active, trimeric unit, characterized by a unique C-terminal helix bearing an actinobacterial specific insertion that precludes larger protein oligomerization. This particular feature, together with the presence of an odhA gene coding for both the decarboxylase and the acyltransferase domains on the same polypetide, is spread over Actinobacteria and reflects the association of PDH and ODH into a single physical complex. Considering the central role of the pyruvate and 2-oxoglutarate nodes in central metabolism, our findings pave the way to both therapeutic and metabolic engineering applications.

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