scholarly journals Rearrangement of nucleosomal components by modification of histone amino groups. Structural role of lysine residues

Biochemistry ◽  
1984 ◽  
Vol 23 (19) ◽  
pp. 4280-4284 ◽  
Author(s):  
Juan Jordano ◽  
Francisco Montero ◽  
Enrique Palacian
1986 ◽  
Vol 11 (1) ◽  
pp. 47-50 ◽  
Author(s):  
A. Vioque ◽  
F. Hern�ndez ◽  
E. Palaci�n

1983 ◽  
Vol 49 (03) ◽  
pp. 208-213
Author(s):  
A J Osbahr

SummaryThe modification of canine fibrinogen with citraconic anhydride modified the ε-amino groups of the fibrinogen and at the same time generated additional negative charges into the protein. The addition of thrombin to the modified fibrinogen did not induce polymerization; however, the fibrinopeptide was released at a faster rate than from the unmodified fibrinogen. The physical properties of the citraconylated fibrinogen were markedly altered by the modification of 50-60 lysine residues in one hour. A modified fibrinopeptide-A was released by thrombin from the modified fibrinogen and was electrophoretically more anionic than the unmodified fibrinopeptide-A. Edman analysis confirmed the modification of the lysine residue present in the peptide. The rate of removal of citraconylated fibrinopeptide-A from modified fibrinogen by thrombin was 30 to 40 percent greater than the cleavage of unmodified fibrinopeptide-A from unmodified fibrinogen. However, the modification of 60 or more lysine residues in the fibrinogen produced a decrease in the rate of cleavage of citraconylated fibrinopeptide-A. The results suggest that additional negative charge in the vicinity of the attachment of fibrinopeptide-A to canine fibrinogen aids in the removal of the peptide by thrombin.


2018 ◽  
Vol 24 (26) ◽  
pp. 3072-3083 ◽  
Author(s):  
Sowndramalingam Sankaralingam ◽  
Angham Ibrahim ◽  
MD Mizanur Rahman ◽  
Ali H. Eid ◽  
Shankar Munusamy

Background: The incidence and prevalence of diabetes mellitus are increasing globally at alarming rates. Cardiovascular and renal complications are the major cause of morbidity and mortality in patients with diabetes. Methylglyoxal (MG) - a highly reactive dicarbonyl compound – is increased in patients with diabetes and has been implicated to play a detrimental role in the etiology of cardiovascular and renal complications. Derived from glucose, MG binds to arginine and lysine residues in proteins, and the resultant end products serve as surrogate markers of MG generation in vivo. Under normal conditions, MG is detoxified by the enzyme glyoxalase 1 (Glo1), using reduced glutathione as a co-factor. Elevated levels of MG is known to cause endothelial and vascular dysfunction, oxidative stress and atherosclerosis; all of which are risk factors for cardiovascular diseases. Moreover, MG has also been shown to cause pathologic structural alterations and impair kidney function. Conversely, MG scavengers (such as N-acetylcysteine, aminoguanidine or metformin) or Nrf2/Glo1 activators (such as trans-resveratrol / hesperetin) are shown to be useful in preventing MG-induced cardiovascular and renal complications in diabetes. However, clinical evidence supporting the MG lowering properties of these agents are limited and hence, need further investigation. Conclusion: Reducing MG levels directly using scavengers or indirectly via activation of Nrf2/Glo1 may serve as a novel and potent therapeutic strategy to counter the deleterious effects of MG in diabetic complications.


1987 ◽  
Vol 105 (3) ◽  
pp. 1463-1469 ◽  
Author(s):  
C Fornieri ◽  
M Baccarani-Contri ◽  
D Quaglino ◽  
I Pasquali-Ronchetti

Hydrophobic tropoelastin molecules aggregate in vitro in physiological conditions and form fibers very similar to natural ones (Bressan, G. M., I. Pasquali Ronchetti, C. Fornieri, F. Mattioli, I. Castellani, and D. Volpin, 1986, J. Ultrastruct. Molec. Struct. Res., 94:209-216). Similar hydrophobic interactions might be operative in in vivo fibrogenesis. Data are presented suggesting that matrix glycosaminoglycans (GAGs) prevent spontaneous tropoelastin aggregation in vivo, at least up to the deamination of lysine residues on tropoelastin by matrix lysyl oxidase. Lysyl oxidase inhibitors beta-aminopropionitrile, aminoacetonitrile, semicarbazide, and isonicotinic acid hydrazide were given to newborn chicks, to chick embryos, and to newborn rats, and the ultrastructural alterations of the aortic elastic fibers were analyzed and compared with the extent of the enzyme inhibition. When inhibition was greater than 65% all chemicals induced alterations of elastic fibers in the form of lateral aggregates of elastin, which were always permeated by cytochemically and immunologically recognizable GAGs. The number and size of the abnormal elastin/GAGs aggregates were proportional to the extent of lysyl oxidase inhibition. The phenomenon was independent of the animal species. All data suggest that, upon inhibition of lysyl oxidase, matrix GAGs remain among elastin molecules during fibrogenesis by binding to positively charged amino groups on elastin. Newly synthesized and secreted tropoelastin has the highest number of free epsilon amino groups, and, therefore, the highest capability of binding to GAGs. These polyanions, by virtue of their great hydration and dispersing power, could prevent random spontaneous aggregation of hydrophobic tropoelastin in the extracellular space.


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