Intrinsic folding of the cysteine residue: competition between folded and extended forms mediated by the –SH group

2020 ◽  
Vol 22 (36) ◽  
pp. 20284-20294
Author(s):  
Gildas Goldsztejn ◽  
Venkateswara Rao Mundlapati ◽  
Valérie Brenner ◽  
Eric Gloaguen ◽  
Michel Mons ◽  
...  

A dual microwave and optical spectroscopic study of a capped cysteine amino acid isolated in a supersonic expansion, combined with quantum chemistry modelling, enabled us to access the conformational preferences of Cys embedded in a protein chain.

2021 ◽  
Vol 125 (16) ◽  
pp. 3244-3256
Author(s):  
Pham Vu Nhat ◽  
Nguyen Thanh Si ◽  
Nguyen Thanh Tien ◽  
Minh Tho Nguyen

2001 ◽  
Vol 360 (3) ◽  
pp. 651-656 ◽  
Author(s):  
Arun GOYAL ◽  
Xing-Guo WANG ◽  
Paul C. ENGEL

Hybrid hexamers were made by refolding mixtures of two mutant forms of clostridial glutamate dehydrogenase. Mutant Cys320Ser (C320S) has a similar activity to the wild-type enzyme, but is unreactive with Ellman's reagent, 5,5′-dithiobis(2-nitrobenzoate) (DTNB). The triple mutant Lys89Leu/Ala163Gly/Ser380Ala (K89L/A163G/S380A), active with norleucine but not glutamate, is inactivated by DTNB, since the amino acid residue at position 320 is a cysteine residue. The chosen ratio favoured 1:5 hybrids of the triple mutant and C320S. The renatured mixture was treated with DTNB and separated on an NAD+–agarose column to which only C320S subunits bind tightly. Fractions were monitored for glutamate and norleucine activity and for releasable thionitrobenzoate to establish subunit stoichiometry. A fraction highly enriched in the 1:5 hybrid was identified. Homohexamers (C320S with 40mM glutamate and 1mM NAD+ at pH8.8, or K89L/A163G/S380A with 70mM norleucine and 1mM NAD+ at pH8.5) showed allosteric activation; succinate activated C320S approx. 50-fold (EC50 = 70mM, h = 2.4), and glutarate gave approx. 30-fold activation (EC50 = 35mM, h = 2.3). For the triple mutant, corresponding values were 80mM and 2.2 for succinate, and 75mM and 1.7 for glutarate, but maximal activation was only about 2-fold. In the 1:5 hybrid, with only one norleucine-active subunit per hexamer, responses to glutarate and succinate were still co-operative, and activation was more extensive than in the triple mutant homohexamer. A single norleucine-active subunit can thus respond co-operatively to a substrate analogue at the other five inactive sites. On the other hand, similar hyperbolic dependence on the norleucine concentration for the hybrid and the triple mutant homohexamer reflected the inability of C320S subunits to bind norleucine. With glutamate at pH8.8, an h value of 3.6 was obtained for the 1:5 hybrid, in contrast with an h value of 5.2 for the C320S homohexamer. The ‘foreign’ subunit evidently impedes inter-subunit communication to some extent.


1986 ◽  
Vol 6 (10) ◽  
pp. 3470-3480 ◽  
Author(s):  
E Moran ◽  
B Zerler ◽  
T M Harrison ◽  
M B Mathews

The transformation and early adenovirus gene transactivation functions of the E1A region were analyzed with deletion and point mutations. Deletion of amino acids from position 86 through 120 had little effect on the lytic or transforming functions of the E1A products, while deletion of amino acids from position 121 through 150 significantly impaired both functions. The sensitivity of the transformation function to alterations in the region from amino acid position 121 to 150 was further indicated by the impairment of transforming activity resulting from single amino acid substitutions at positions 124 and 135. Interestingly, conversion of a cysteine residue at position 124 to glycine severely impaired the transformation function without affecting the early adenovirus gene activating functions. Single amino acid substitutions in a different region of the E1A gene had the converse effect. All the mutants produced polypeptides of sufficient stability to be detected by Western immunoblot analysis. The single amino acid substitutions at positions 124 and 135, although impairing the transformation functions, did not detectably alter the formation of the higher-apparent-molecular-weight forms of the E1A products.


1998 ◽  
Vol 64 (5) ◽  
pp. 1650-1656 ◽  
Author(s):  
Peter W. Coschigano ◽  
Thomas S. Wehrman ◽  
L. Y. Young

ABSTRACT The denitrifying strain T1 is able to grow with toluene serving as its sole carbon source. Two mutants which have defects in this toluene utilization pathway have been characterized. A clone has been isolated, and subclones which contain tutD and tutE, two genes in the T1 toluene metabolic pathway, have been generated. ThetutD gene codes for an 864-amino-acid protein with a calculated molecular mass of 97,600 Da. The tutE gene codes for a 375-amino-acid protein with a calculated molecular mass of 41,300 Da. Two additional small open reading frames have been identified, but their role is not known. The TutE protein has homology to pyruvate formate-lyase activating enzymes. The TutD protein has homology to pyruvate formate-lyase enzymes, including a conserved cysteine residue at the active site and a conserved glycine residue that is activated to a free radical in this enzyme. Site-directed mutagenesis of these two conserved amino acids shows that they are also essential for the function of TutD.


2019 ◽  
Vol 43 (4) ◽  
Author(s):  
Listya Purnamasari ◽  
Ali Agus ◽  
Cuk Tri Noviandi

This research aimed to observe the interaction of methionine-cysteine amino acid supplementation to decrease the effect of aflatoxin B1 (AFB1) on diet against production performance of broiler chicken. A number of 240 mixed sex broiler chickens were treated in 9 treatments by factorial design 3 x 3 with methionine-cysteine amino acid (M+C) (75,100, dan 125%) factors and AFB1 levels (0, 200, dan 400 ppb). Variables observed were: Weight gain, feed consumption, and feed conversion ratio (FCR). The results showed that increased AFB1 content in diet from 0 to 400 ppb increased chicken body weight (P <0.05) in each age group. The high body weight was balanced with high feed consumption along with increased nutrient needs, mainly sulfuric amino acid (M+C) as the precursor of glutathione to eliminate toxic through conjugation reactions. The interaction effect was firstly occurred between M + C and AFB1 treatment (P <0.05). Meanwhile increased supplementation of M + C from 75 to 125% caused decreased feed consumption in each age group of chickens, but increased AFB1 levels further increased feed consumption (P<0.05). The interaction effect between the level of M + C and AFB1 contamination in diets on feed consumption were seen in 21-day-old chickens (P<0.05). FCR was also increased (P <0.05) with the reduction of M + C content in diet at 7 days old. The effect of AFB1 on diet and interaction between M + C and AFB1 on chicken FCR in this study was not significant in all age groups. It can be concluded from the current study that supplying methionine-cystine amino acid with 75, 100 and 125% in AFB1 contaminated diet of 0, 200 and 400 ppb improves the performance of broiler chicken production.


2008 ◽  
Vol 112 (36) ◽  
pp. 11189-11193 ◽  
Author(s):  
Joo Yun Lee ◽  
Byung Jin Byun ◽  
Young Kee Kang

1968 ◽  
Vol 108 (5) ◽  
pp. 861-866 ◽  
Author(s):  
S. S. Husain ◽  
G. Lowe

Papain that had been irreversibly inhibited with 1,3-dibromo[2−14C]acetone was reduced with sodium borohydride and carboxymethylated with iodoacetic acid. After digestion with trypsin and α-chymotrypsin the radioactive peptides were purified chromatographically. Their amino acid composition indicated that cysteine-25 and histidine-106 were cross-linked. Since cysteine-25 is known to be the active-site cysteine residue, histidine-106 must be the active-site histidine residue.


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