scholarly journals Specific cyanylation and cleavage at cysteine-104 human hemoglobin α-chain. A novel approach to the problem of the α-chain tryptic core in the study of haemoglobin variants by ‘fingerprinting’ methods

1975 ◽  
Vol 145 (2) ◽  
pp. 251-261 ◽  
Author(s):  
R Casey ◽  
A Lang
Keyword(s):  
Gel Filtration ◽  
Peptide Bond ◽  
Complete Sequence ◽  
Cysteine Residue ◽  
Sequence Information ◽  
Human Haemoglobin ◽  
Alpha Chain ◽  
Novel Approach ◽  
Α Chain

1. A new approach to the analysis, by “fingerprinting”, of the tryptic core region of human haemoglobin alpha-chain is described. 2. The alpha-chain is cyanylated at its single cysteine residue (alpha104) and then split, by exposure to mild alkali, at the N-peptide bond of the resulting beta-thiocyanoalanine residue. 3. The two cleavage fragments, alpha1-103 and alpha104-141, are separated by gel filtration, and the fragment alpha104-141, which contains all the residues of the alpha-chain tryptic core, is digested with pepsin. 4. Preparative “fingerprints” of these peptic peptides yield eight major peptides, which provide complete sequence information for the whole region alpha104-141. 5. The utility of the method is demonstrated by repeating the determination of the substitution in haemoglobin Hopkins-2, a known alpha-chain core variant in which histidine-alpha112 (G19) is replaced by an aspartic acid residue.

scholarly journals A novel and comprehensive synthetic approach for the elucidation of protein antigenic structures. Determination of the full antigenic profile of the α-chain of human haemoglobin

1980 ◽  
Vol 191 (1) ◽  
pp. 261-264 ◽  
Author(s):  
A L Kazim ◽  
M Z Atassi
Keyword(s):  
Primary Structure ◽  
Synthetic Approach ◽  
Human Haemoglobin ◽  
Alpha Chain ◽  
Antigenic Sites ◽  
Full Profile ◽  
Α Chain ◽  
First Time ◽  
Antigenic Profile

A comprehensive synthetic approach for the determination of continuous antigenic sites of proteins is presented. This approach consists of the synthesis of a series of consecutive overlapping peptides that, together, systematically represent the entire primary structure of the protein under study. Its application to the alpha-chain of human haemoglobin afforded, for the first time, a full profile of immunochemically active alpha-chain peptides and enabled the localization of all the major continuous antigenic sites of this haemoglobin subunit.

scholarly journals The primary structure of alamethicin

1970 ◽  
Vol 117 (4) ◽  
pp. 757-766 ◽  
Author(s):  
J. W. Payne ◽  
R. Jakes ◽  
B. S. Hartley
Keyword(s):  
Action Potentials ◽  
Model Building ◽  
Cyclic Peptide ◽  
Peptide Bond ◽  
Complete Sequence ◽  
Carboxyl Group ◽  
Imino Group ◽  
Synthetic Membranes ◽  
Enzymic Digestion

Alamethicin, an antibiotic that can transport cations and induce action potentials in synthetic membranes, is shown to be a cyclic peptide with 18 residues including 7-α-aminoisobutyric acid residues, two glutamine residues and one free carboxyl group. The composition indicates microheterogeneity. Alamethicin itself and many peptides derived from it are immune to enzymic digestion, but specific partial acid cleavages have allowed determination of the complete sequence. Diborane reduction has shown that the α-carboxyl group of glutamine-18 is free, but the ring is formed by a peptide bond between the imino group of proline-1 and the γ-carboxyl group of glutamic acid-17. The structure is contrasted with that of other cation-transporting antibiotics. Model building allows a structure that could stack to form a tunnel with a lipophilic exterior and hydrophilic interior and flexible internal arms formed by the pendant C-terminal glutamine residue.

scholarly journals Haemoglobin binding with haptoglobin. Localization of the haptoglobin-binding site on the α-chain of human haemoglobin

1981 ◽  
Vol 197 (2) ◽  
pp. 507-510 ◽  
Author(s):  
A L Kazim ◽  
M Z Atassi
Keyword(s):  
Binding Site ◽  
Synthetic Approach ◽  
Protein Chain ◽  
Human Haemoglobin ◽  
Alpha Chain ◽  
Α Chain

A synthetic approach was employed to identify the haptoglobin-binding site on the alpha-chain of human haemoglobin. This approach cosists of the synthesis of a series of consecutive overlapping peptides that, together, systematically represent the entire protein chain. Fourteen peptides were synthesized (alpha 1-15, alpha 11-25, alpha 21-35, alpha 31-45, alpha 41-55, alpha 51-65, alpha 61-75, alpha 71-85, alpha 81-95, alpha 91-105, alpha 101-115, alpha 111-125, alpha 121-135 and alpha 131-141), and their ability bind human haptoglobin was studied, Only peptide alpha 121-135 bound haptoglobin significantly. On this basis we conclude that the haptoglobin-binding site on the alpha-chain of haemoglobin resides within, but does not necessarily encompass all of, the region alpha 121-135.

Determination of complete sequence information of the human ABO blood group orthologous gene in pigs and breed difference in blood type frequencies

Gene ◽  
2018 ◽  
Vol 640 ◽  
pp. 1-5 ◽  
Author(s):  
Min-Kyeung Choi ◽  
Minh Thong Le ◽  
Hyesun Cho ◽  
Joori Yum ◽  
Mingue Kang ◽  
...  
Keyword(s):  
Blood Group ◽  
Orthologous Gene ◽  
Complete Sequence ◽  
Blood Type ◽  
Sequence Information ◽  
Abo Blood Group ◽  
Breed Difference

The Use of TMAH to Etch Silicon and Expose Metal Bridging Failures

2000 ◽  
Author(s):  
Mark Morris ◽  
James Mohr ◽  
Esteban Ortiz ◽  
Steven Englebretson
Keyword(s):  
Failure Mechanism ◽  
Schottky Diodes ◽  
Tetramethylammonium Hydroxide ◽  
Novel Approach ◽  
Failure Location ◽  
Metal Etching ◽  
Plastic Mold

Abstract Determination of metal bridging failures on plastic encapsulated devices is difficult due to the metal etching effects that occur while removing many of the plastic mold compounds. Typically, the acids used to remove the encapsulation are corrosive to the metals that are found within the device. Thus, decapsulation can result in removal of the failure mechanism. Mechanical techniques are often not successful due to damage that results in destruction of the die and failure mechanism. This paper discusses a novel approach to these types of failures using a silicon etch and a backside evaluation. The desirable characteristics of the technique would be to remove the silicon and leave typical device metals unaffected. It would also be preferable that the device passivation and oxides not be etched so that the failure location is not disturbed. The use of Tetramethylammonium Hydroxide (TMAH), was found to fit these prerequisites. The technique was tested on clip attached Schottky diodes that exhibited resistive shorting. The use of the TMAH technique was successful at exposing thin solder bridges that extruded over the edge of the die resulting in failure.

scholarly journals Crystallization and X-ray diffraction data analysis of human deoxyhaemoglobin A0 fully stripped of any anions

1999 ◽  
Vol 55 (11) ◽  
pp. 1914-1916 ◽  
Author(s):  
F. A. V. Seixas ◽  
W. F. de Azevedo ◽  
M. F. Colombo
Keyword(s):  
Diffraction Data ◽  
Oxygen Affinity ◽  
X Ray Diffraction ◽  
Structural Explanation ◽  
Human Haemoglobin ◽  
X Ray ◽  
High Resolution Structure ◽  
Allosteric Properties

In this work, initial crystallographic studies of human haemoglobin (Hb) crystallized in isoionic and oxygen-free PEG solution are presented. Under these conditions, functional measurements of the O2-linked binding of water molecules and release of protons have evidenced that Hb assumes an unforeseen new allosteric conformation. The determination of the high-resolution structure of the crystal of human deoxy-Hb fully stripped of anions may provide a structural explanation for the role of anions in the allosteric properties of Hb and, particularly, for the influence of chloride on the Bohr effect, the mechanism by which Hb oxygen affinity is regulated by pH. X-ray diffraction data were collected to 1.87 Å resolution using a synchrotron-radiation source. Crystals belong to the space group P21212 and preliminary analysis revealed the presence of one tetramer in the asymmetric unit. The structure is currently being refined using maximum-likelihood protocols.

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