Conformational dynamics and kinetics of peptide antagonist interactions with interleukin-1 receptor. Fluorescence studies using the NBD-labelled peptide AF12415

2009 ◽  
Vol 49 (5) ◽  
pp. 444-454 ◽  
Author(s):  
DAVID J. COWLEY ◽  
ANDREAS J. SCHULZE
Keyword(s):  
Interleukin 1 ◽  
Conformational Dynamics ◽  
Fluorescence Studies ◽  
Peptide Antagonist ◽  
Kinetics Of

Conformational dynamics and pre-steady-state kinetics of DNA glycosylases

2010 ◽  
Vol 75 (10) ◽  
pp. 1225-1239 ◽  
Author(s):  
O. S. Fedorova ◽  
N. A. Kuznetsov ◽  
V. V. Koval ◽  
D. G. Knorre
Keyword(s):  
Steady State ◽  
Conformational Dynamics ◽  
Dna Glycosylases ◽  
Steady State Kinetics ◽  
Kinetics Of

scholarly journals Oversized galactosides as a probe for conformational dynamics in LacY

2018 ◽  
Vol 115 (16) ◽  
pp. 4146-4151 ◽  
Author(s):  
Irina Smirnova ◽  
Vladimir Kasho ◽  
Xiaoxu Jiang ◽  
Hong-Ming Chen ◽  
Stephen G. Withers ◽  
...  
Keyword(s):  
Binding Site ◽  
Conformational Dynamics ◽  
Dissociation Rate ◽  
Binding Kinetics ◽  
Lactose Permease ◽  
E Coli ◽  
Open Conformation ◽  
Dissociation Rate Constants ◽  
Kinetics Of ◽  
Micromolar Range

Binding kinetics of α-galactopyranoside homologs with fluorescent aglycones of different sizes and shapes were determined with the lactose permease (LacY) of Escherichia coli by FRET from Trp151 in the binding site of LacY to the fluorophores. Fast binding was observed with LacY stabilized in an outward-open conformation (kon = 4–20 μM−1·s−1), indicating unobstructed access to the binding site even for ligands that are much larger than lactose. Dissociation rate constants (koff) increase with the size of the aglycone so that Kd values also increase but remain in the micromolar range for each homolog. Phe27 (helix I) forms an apparent constriction in the pathway for sugar by protruding into the periplasmic cavity. However, replacement of Phe27 with a bulkier Trp does not create an obstacle in the pathway even for large ligands, since binding kinetics remain unchanged. High accessibility of the binding site is also observed in a LacY/nanobody complex with partially blocked periplasmic opening. Remarkably, E. coli expressing WT LacY catalyzes transport of α- or β-galactopyranosides with oversized aglycones such as bodipy or Aldol518, which may require an extra space within the occluded intermediate. The results confirm that LacY specificity is strictly directed toward the galactopyranoside ring and also clearly indicate that the opening on the periplasmic side is sufficiently wide to accommodate the large galactoside derivatives tested here. We conclude that the actual pathway for the substrate entering from the periplasmic side is wider than the pore diameter calculated in the periplasmic-open X-ray structures.

Kinetics of cytokine expression during healing of acute colitis in mice

1996 ◽  
Vol 271 (1) ◽  
pp. G130-G136 ◽  
Author(s):  
L. A. Dieleman ◽  
C. O. Elson ◽  
G. S. Tennyson ◽  
K. W. Beagley
Keyword(s):  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Interleukin 1 ◽  
Rna Extraction ◽  
Cytokine Expression ◽  
Tnf Alpha ◽  
Colonic Injury ◽  
Necrosis Factor Alpha ◽  
Inflammatory Protein ◽  
Kinetics Of

The mechanisms of wound healing in the gut are poorly understood but are mediated by cytokines in other tissues. In this study we wanted to determine which cytokines were expressed after nonspecific colonic injury, the kinetics of that expression, and how cytokine expression correlated with tissue histology. At 0, 4, 8, 12, 24, 48, and 72 h after intrarectal administration of 3% acetic acid to C3H/HeJ mice, their colons were removed for histology, organ culture, and RNA extraction. Cytokine mRNA expression for various cytokines was assessed by reverse transcriptase-polymerase chain reaction with primers specific for each cytokine. Cytokine production in organ cultures was measured with bioassays. Shortly after colonic injury and during colonic regeneration, proinflammatory cytokines such as interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein (MIP), and transforming growth factor-beta (TGF-beta) were expressed. In contrast, expression of T cell-derived cytokines was not detected at any time point. Cytokines such as IL-1 beta, IL-6, IL-10, TNF-alpha, and MIP-1 are important mediators of tissue repair and restitution after nonspecific colonic injury and may subserve a similar role in human colitis.

In vivo E-selectin upregulation correlates early with infiltration of PMN, later with PBL entry: MAbs block both

1996 ◽  
Vol 270 (1) ◽  
pp. H183-H193 ◽  
Author(s):  
R. M. Binns ◽  
S. T. Licence ◽  
A. A. Harrison ◽  
E. T. Keelan ◽  
M. K. Robinson ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Interleukin 1 ◽  
Inflammatory Infiltration ◽  
Necrosis Factor Alpha ◽  
Inflammatory Processes ◽  
Factor Alpha ◽  
Kinetics Of ◽  
Necrosis Factor

The endothelial molecule E-selectin binds most leukocyte subsets in vitro. Yet its role in regulating the very different kinetics of inflammatory infiltration of different leukocyte subsets in vivo is unclear. The kinetics of E-selectin upregulation and polymorphonuclear leukocyte (PMN) and blood lymphocyte (PBL) localization in inflammation induced by interleukin-1 alpha (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), phytohemagglutinin (PHA), and phorbol myristate acetate (PMA) were investigated in a well-established inbred pig trafficking model. They differed markedly both for these three labeled indicators of inflammation and in each of the four inflammatory processes. In each, E-selectin upregulation correlated with early PMN entry and later with PBL infiltration but was more protracted than both. The importance of E-selectin was confirmed by marked inhibition of PMN and PBL entry (up to > 60%) by F(ab')2 anti-E-selectin. Involvement of other molecules was illustrated by similar or greater inhibition with anti-CD18 F(ab')2. We conclude that, like CD18, E-selectin is necessary for most PMN and PBL infiltration but alone is insufficient, consistent with the involvement of several alternative multistep molecular mechanisms in this entry.

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