Comparison of physico-chemical aspects between E. coli and human dihydrofolate reductase: an equilibrium unfolding study

BIOPHYSICS ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 378-386 ◽  
Author(s):  
Charu Thapliyal ◽  
Neha Jain ◽  
Pratima Chaudhuri
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya ◽  
Kyra Carbone ◽  
Martha Simon ◽  
Beth Lin ◽  
...  

A recently developed 1.4 nm gold cluster has been found to be useful in labeling macromolecular sites to 1-3 nm resolution. The gold compound is organically derivatized to contain a monofunctional arm for covalent linking to biomolecules. This may be used to mark a specific site on a structure, or to first label a component and then reassemble a multicomponent macromolecular complex. Two examples are given here: the chaperonin groEL and ribosomes.Chaperonins are essential oligomeric complexes that mediate nascent polypeptide chain folding to produce active proteins. The E. coli chaperonin, groEL, has two stacked rings with a central hole ∽6 nm in diameter. The protein dihydrofolate reductase (DHFR) is a small protein that has been used in chain folding experiments, and serves as a model substrate for groEL. By labeling the DHFR with gold, its position with respect to the groEL complex can be followed. In particular, it was sought to determine if DHFR refolds on the external surface of the groEL complex, or whether it interacts in the central cavity.


2018 ◽  
Vol 36 (No. 5) ◽  
pp. 378-385
Author(s):  
Vytautas Januskevicius ◽  
Grazina Januskeviciene ◽  
Gintare Zaborskiene

The aim of this study was to investigate the possible harmful effect of Sarcocystis parasites on bovine diaphragm meat quality. Meat samples were collected from 120 bulls aged 20–24 months. Meat quality was investigated using microbiological and physico-chemical (RP-HPLC, GC) methods 48 hours after slaughter. Sarcocystis infection was associated with increased fat content, lightness L* and drip loss, and decreased ash and protein percentages. Infection also had a significant effect on the amount of amino acids (AAs), which slowly decreased as the number of sarcocysts increased. The total amount of AAs correlated with glutamic acid content (R = 0.966, P &lt; 0.05). Heavily infected samples contained significantly lower amounts of putrescine, histamine, spermine and spermidine (P &lt; 0.05) and<br /> a noticeable increase in the total count of aerobic microorganisms, but no change in the numbers of E. coli and coliform bacteria in comparison with no infected samples. Sarcocysts in beef diaphragms did not cause serious changes in the technological quality of the meat, but the biological quality of infected meat was reduced.  


Author(s):  
Vladislav Naumovich ◽  
Maria Grishina ◽  
Jurica Novak ◽  
Prateek Pathak ◽  
Vladimir Potemkin ◽  
...  

Biochemistry ◽  
1990 ◽  
Vol 29 (40) ◽  
pp. 9467-9479 ◽  
Author(s):  
Jay F. Davies ◽  
Tavner J. Delcamp ◽  
Neal J. Prendergast ◽  
Victor A. Ashford ◽  
James H. Freisheim ◽  
...  

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