Cysteine Residues Are Involved in Structure and Function of Melanocortin 1 Receptor: Substitution of a Cysteine Residue in Transmembrane Segment Two Converts an Agonist to Antagonist

2001 ◽  
Vol 281 (4) ◽  
pp. 851-857 ◽  
Author(s):  
Per-Anders Frändberg ◽  
Marina Doufexis ◽  
Supriya Kapas ◽  
Vijay Chhajlani
2020 ◽  
pp. jbc.RA120.016126
Author(s):  
Katarina Wang ◽  
Marah Maayah ◽  
Joann B. Sweasy ◽  
Khadijeh S. Alnajjar

8-oxoguanine glycosylase (OGG1) is a base excision repair enzyme responsible for the recognition and removal of 8-oxoguanine, a commonly occurring oxidized DNA modification. OGG1 prevents the accumulation of mutations and regulates the transcription of various oxidative stress-response genes. In addition to targeting DNA, oxidative stress can affect proteins like OGG1 itself, specifically at cysteine residues. Previous work has shown that the function of OGG1 is sensitive to oxidants, with the cysteine residues of OGG1 being the most likely site of oxidation. Due to the integral role of OGG1 in maintaining cellular homeostasis under oxidative stress, it is important to understand the effect of oxidants on OGG1 and the role of cysteines in its structure and function. In this study, we investigate the role of the cysteine residues in the function of OGG1 by mutating and characterizing each cysteine residue. Our results indicate that the cysteines in OGG1 fall into four functional categories: those that are necessary for (1) glycosylase activity (C146 and C255), (2) lyase activity (C140S, C163, C241 and C253), (3) structural stability (C253), and (4) those with no known function (C28 and C75). These results suggest that under conditions of oxidative stress, cysteine can be targeted for modifications, thus altering the response of OGG1 and affecting its downstream cellular functions.


2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
J. Santiago Mejia ◽  
Erik N. Arthun ◽  
Richard G. Titus

One approach to identify epitopes that could be used in the design of vaccines to control several arthropod-borne diseases simultaneously is to look for common structural features in the secretome of the pathogens that cause them. Using a novel bioinformatics technique, cysteine-abundance and distribution analysis, we found that many different proteins secreted by several arthropod-borne pathogens, includingPlasmodium falciparum, Borrelia burgdorferi, and eight species of Proteobacteria, are devoid of cysteine residues. The identification of three cysteine-abundance and distribution patterns in several families of proteins secreted by pathogenic and nonpathogenic Proteobacteria, and not found when the amino acid analyzed was tryptophan, provides evidence of forces restricting the content of cysteine residues in microbial proteins during evolution. We discuss these findings in the context of protein structure and function, antigenicity and immunogenicity, and host-parasite relationships.


2010 ◽  
Vol 38 (5) ◽  
pp. 1378-1385 ◽  
Author(s):  
Sigrid Egger ◽  
Apirat Chaikuad ◽  
Kathryn L. Kavanagh ◽  
Udo Oppermann ◽  
Bernd Nidetzky

Biosynthesis of the glycosaminoglycan precursor UDP-α-D-glucuronic acid occurs through a 2-fold oxidation of UDP-α-D-glucose that is catalysed by UGDH (UDP-α-D-glucose 6-dehydrogenase). Structure–function relationships for UGDH and proposals for the enzymatic reaction mechanism are reviewed in the present paper, and structure-based sequence comparison is used for subclassification of UGDH family members. The eukaryotic group of enzymes (UGDH-II) utilize an extended C-terminal domain for the formation of complex homohexameric assemblies. The comparably simpler oligomerization behaviour of the prokaryotic group of enzymes (UGDH-I), in which dimeric forms prevail, is traced back to the lack of relevant intersubunit contacts and trimmings within the C-terminal region. The active site of UGDH contains a highly conserved cysteine residue, which plays a key role in covalent catalysis. Elevated glycosaminoglycan formation is implicated in a variety of human diseases, including the progression of tumours. The inhibition of synthesis of UDP-α-D-glucuronic acid using UGDH antagonists might therefore be a useful strategy for therapy.


Science ◽  
1987 ◽  
Vol 236 (4806) ◽  
pp. 1315-1318 ◽  
Author(s):  
N. Giese ◽  
K. Robbins ◽  
S. Aaronson

2005 ◽  
Vol 33 (1) ◽  
pp. 108-111 ◽  
Author(s):  
E. Theodoratou ◽  
R. Huber ◽  
A. Böck

Hydrogenase maturation endopeptidases catalyse the terminal step in the maturation of the large subunit of [NiFe]-hydrogenases. They remove a C-terminal extension from the precursor of the subunit, triggering a conformational switch that results in the bridging of the Fe and Ni atoms of the metal centre via the thiolate of a cysteine residue and in closure of the centre. This review summarizes what is known about the structure of the protein, its substrate specificity and its possible reaction mechanism.


2000 ◽  
Vol 28 (5) ◽  
pp. A266-A266
Author(s):  
M. Doufexis ◽  
P-A Frändberg ◽  
S. Kapas ◽  
V. Chhajlani

Virology ◽  
2005 ◽  
Vol 332 (2) ◽  
pp. 550-562 ◽  
Author(s):  
Tina M. Cairns ◽  
Daniel J. Landsburg ◽  
J. Charles Whitbeck ◽  
Roselyn J. Eisenberg ◽  
Gary H. Cohen

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