scholarly journals Amino Acid Residues Important for Folding of Thioredoxin Are Revealed Only by Study of the Physiologically Relevant Reduced Form of the Protein

Biochemistry ◽  
2010 ◽  
Vol 49 (41) ◽  
pp. 8922-8928 ◽  
Author(s):  
Damon Huber ◽  
Alain Chaffotte ◽  
Markus Eser ◽  
Anne-Gaëlle Planson ◽  
Jon Beckwith
Keyword(s):  
Amino Acid ◽  
Reduced Form ◽  
Amino Acid Residues

Purification and Characterization of Cytochrome 553 from the Chrysophycean Alga Monochrysis lutheri

1971 ◽  
Vol 49 (6) ◽  
pp. 641-646 ◽  
Author(s):  
M. V. Laycock ◽  
J. S. Craigie
Keyword(s):  
Amino Acid ◽  
Higher Plants ◽  
Sedimentation Coefficient ◽  
Cytochrome F ◽  
Reduced Form ◽  
Amino Acid Residues ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Equilibrium Centrifugation

Cytochrome 553, an electron carrier in photosynthesis and a functional analogue of cytochrome f of higher plants, was isolated from Monochrysis lutheri and purified by salt fractionation, chromatography, and isoelectric focussing. Absorption maxima occurred at 275, 320, 416, 523, and 553 nm in the reduced form. The α-absorption peak was symmetrical and had an extinction coefficient of 25.9 mM−1 cm−1. The molecular weight was 11 100 by equilibrium centrifugation, 12 400 from iron determinations, and 10 300 from the amino acid composition. The molecule consisted of one heme group and 91 amino acid residues including two cysteine residues and one each of histidine, arginine, tryptophan, methionine, and proline. Other physical properties measured were: the sedimentation coefficient, 1.3 S; the normal oxidation reduction potential, + 0.388 V; and the isoelectric point, pH 3.75.

Substrate Recognition by Vitamin K-Dependent Carboxylase

1987 ◽  
Vol 57 (01) ◽  
pp. 017-019 ◽  
Author(s):  
Magda M W Ulrich ◽  
Berry A M Soute ◽  
L Johan M van Haarlem ◽  
Cees Vermeer
Keyword(s):  
Amino Acid ◽  
Vitamin K ◽  
Substrate Recognition ◽  
Bovine Liver ◽  
Amino Acid Residues

SummaryDecarboxylated osteocalcins were prepared and purified from bovine, chicken, human and monkey bones and assayed for their ability to serve as a substrate for vitamin K-dependent carboxylase from bovine liver. Substantial differences were observed, especially between bovine and monkey d-osteocalcin. Since these substrates differ only in their amino acid residues 3 and 4, it seems that these residues play a role in the recognition of a substrate by hepatic carboxylase.

Statistical Force-Field for Structural Modeling Using Chemical Cross-Linking/mass Spectrometry Distance Constraints

2018 ◽  
Author(s):  
Allan J. R. Ferrari ◽  
Fabio C. Gozzo ◽  
Leandro Martinez
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Force Field ◽  
Protein Structures ◽  
Protein Structure Determination ◽  
Structural Modeling ◽  
Cross Linking ◽  
Amino Acid Residues ◽  
Distance Constraints ◽  
Chemical Cross Linking

<div><p>Chemical cross-linking/Mass Spectrometry (XLMS) is an experimental method to obtain distance constraints between amino acid residues, which can be applied to structural modeling of tertiary and quaternary biomolecular structures. These constraints provide, in principle, only upper limits to the distance between amino acid residues along the surface of the biomolecule. In practice, attempts to use of XLMS constraints for tertiary protein structure determination have not been widely successful. This indicates the need of specifically designed strategies for the representation of these constraints within modeling algorithms. Here, a force-field designed to represent XLMS-derived constraints is proposed. The potential energy functions are obtained by computing, in the database of known protein structures, the probability of satisfaction of a topological cross-linking distance as a function of the Euclidean distance between amino acid residues. The force-field can be easily incorporated into current modeling methods and software. In this work, the force-field was implemented within the Rosetta ab initio relax protocol. We show a significant improvement in the quality of the models obtained relative to current strategies for constraint representation. This force-field contributes to the long-desired goal of obtaining the tertiary structures of proteins using XLMS data. Force-field parameters and usage instructions are freely available at http://m3g.iqm.unicamp.br/topolink/xlff <br></p></div><p></p><p></p>

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