Bifunctional Small Molecules Are Biomimetic Catalysts for Silica Synthesis at Neutral pH

2005 ◽  
Vol 127 (1) ◽  
pp. 325-330 ◽  
Author(s):  
Kristian M. Roth ◽  
Yan Zhou ◽  
Wenjun Yang ◽  
Daniel E. Morse
Keyword(s):  
Small Molecules ◽  
Biomimetic Catalysts ◽  
Neutral Ph ◽  
Silica Synthesis

scholarly journals Site-Selective C-C Modification of Proteins at Neutral pH Using Organocatalyst-Mediated Cross Aldol Ligations

2018 ◽  
Author(s):  
Martin A. Fascione ◽  
Richard J. Spears ◽  
Robin L. Brabham ◽  
Darshita Budhadev ◽  
Tessa Keenan ◽  
...  
Keyword(s):  
Small Molecules ◽  
Stable Carbon ◽  
Biological Mechanisms ◽  
Large Excess ◽  
Reaction Conditions ◽  
Chemical Methods ◽  
Neutral Ph ◽  
Chemical Modification Of Proteins ◽  
A Site ◽  
Site Selective

The bioconjugation of proteins with small molecules has proved an invaluable strategy for probing and perturbing dynamic biological mechanisms. The general use of chemical methods for the functionalisation of proteins remains limited however by the frequent requirement for complicated reaction partners to be present in large excess, and harsh reaction conditions which are incompatible with many protein scaffolds. Herein we describe a site-selective organocatalyst-mediated protein aldol ligation (OPAL) that affords stable carbon-carbon linked bioconjugates at neutral pH under biocompatible conditions. OPAL enables rapid chemical modification of proteins within an hour using simple aldehyde probes in minimal excess, and is utilised here in the selective affinity tagging of proteins in cell lysate. Furthermore we demonstrate that the b-hydroxy aldehyde product of the OPAL can be functionalised a second time at neutral pH in a subsequent organocatalyst-mediated oxime ligation. This tandem strategy is showcased in the ‘chemical mimicry’ of a previously inaccessible natural dual post-translationally modified protein integral to the pathogenesis of the neglected tropical disease Leishmaniasis. <br>

Rapid and Selective Cleavage of Amide Groups at Neutral pH: Applications from Hyaluronic Acid to Small Molecules

2018 ◽  
Vol 2018 (23) ◽  
pp. 2995-3000 ◽  
Author(s):  
Jing Jing ◽  
Johan Bankefors ◽  
Céline Bonneaud ◽  
Elin Sawen ◽  
Thibaud Gerfaud ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Small Molecules ◽  
Neutral Ph

scholarly journals Site-Selective C-C Modification of Proteins at Neutral pH Using Organocatalyst-Mediated Cross Aldol Ligations

2018 ◽  
Author(s):  
Martin A. Fascione ◽  
Richard J. Spears ◽  
Robin L. Brabham ◽  
Darshita Budhadev ◽  
Tessa Keenan ◽  
...  
Keyword(s):  
Small Molecules ◽  
Stable Carbon ◽  
Biological Mechanisms ◽  
Large Excess ◽  
Reaction Conditions ◽  
Chemical Methods ◽  
Neutral Ph ◽  
Chemical Modification Of Proteins ◽  
A Site ◽  
Site Selective

The bioconjugation of proteins with small molecules has proved an invaluable strategy for probing and perturbing dynamic biological mechanisms. The general use of chemical methods for the functionalisation of proteins remains limited however by the frequent requirement for complicated reaction partners to be present in large excess, and harsh reaction conditions which are incompatible with many protein scaffolds. Herein we describe a site-selective organocatalyst-mediated protein aldol ligation (OPAL) that affords stable carbon-carbon linked bioconjugates at neutral pH under biocompatible conditions. OPAL enables rapid chemical modification of proteins within an hour using simple aldehyde probes in minimal excess, and is utilised here in the selective affinity tagging of proteins in cell lysate. Furthermore we demonstrate that the b-hydroxy aldehyde product of the OPAL can be functionalised a second time at neutral pH in a subsequent organocatalyst-mediated oxime ligation. This tandem strategy is showcased in the ‘chemical mimicry’ of a previously inaccessible natural dual post-translationally modified protein integral to the pathogenesis of the neglected tropical disease Leishmaniasis. <br>

Strategy for functionalization of electrodes with discrete, unmodified small molecules exhibiting aqueous stability

2020 ◽  
Vol 8 (31) ◽  
pp. 15681-15686
Author(s):  
Sean Clair ◽  
Michael R. Norris
Keyword(s):  
Small Molecules ◽  
Neutral Ph ◽  
P Immobilization ◽  
Electroactive Molecules

Immobilization of electroactive molecules without synthetic modification that are stable at neutral pH!

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Gap junctions in the prothoracic glands of the tobacco hornworm, Manduca sexta

1992 ◽  
Vol 50 (1) ◽  
pp. 706-707
Author(s):  
Ji-da Dai ◽  
M. Joseph Costello ◽  
Lawrence I. Gilbert
Keyword(s):  
Gap Junctions ◽  
Small Molecules ◽  
Manduca Sexta ◽  
Freeze Fracture ◽  
Cell Communication ◽  
Cellular Level ◽  
Thin Sections ◽  
Prothoracic Glands ◽  
Polyhydroxylated Steroids ◽  
Stimulation Of

Insect molting and metamorphosis are elicited by a class of polyhydroxylated steroids, ecdysteroids, that originate in the prothoracic glands (PGs). Prothoracicotropic hormone stimulation of steroidogenesis by the PGs at the cellular level involves both calcium and cAMP. Cell-to-cell communication mediated by gap junctions may play a key role in regulating signal transduction by controlling the transmission of small molecules and ions between adjacent cells. This is the first report of gap junctions in the PGs, the evidence obtained by means of SEM, thin sections and freeze-fracture replicas.

Fusion and Fission Processes in Exocytosis: Possible Roles for Synexin and Osmotic Lysis in the Two Events

1980 ◽  
Vol 38 ◽  
pp. 594-597
Author(s):  
H.B. Pollard ◽  
C.E. Creutz ◽  
C.J. Pazoles ◽  
J.H. Scott
Keyword(s):  
Small Molecules ◽  
Chromaffin Cells ◽  
Adrenal Glands ◽  
General Concept ◽  
Extracellular Calcium ◽  
Large Protein ◽  
Granule Membrane ◽  
Osmotic Lysis ◽  
Per Se ◽  
Chemical Evidence

Exocytosis is a general concept describing secretion of enzymes, hormones and transmitters that are otherwise sequestered in intracellular granules. Chemical evidence for this concept was first gathered from studies on chromaffin cells in perfused adrenal glands, in which it was found that granule contents, including both large protein and small molecules such as adrenaline and ATP, were released together while the granule membrane was retained in the cell. A number of exhaustive reviews of this early work have been published and are summarized in Reference 1. The critical experiments demonstrating the importance of extracellular calcium for exocytosis per se were also first performed in this system (2,3), further indicating the substantial service given by chromaffin cells to those interested in secretory phenomena over the years.

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