Enzyme Stability

Publication Title: 
Nature Communications

A de novo G608G mutation in LMNA gene leads to Hutchinson-Gilford progeria syndrome. Mice lacking the prelamin A-processing metalloprotease, Zmpste24, recapitulate many of the progeroid features of Hutchinson-Gilford progeria syndrome. Here we show that A-type lamins interact with SUV39H1, and prelamin A/progerin exhibits enhanced binding capacity to SUV39H1, protecting it from proteasomal degradation and, consequently, increasing H3K9me3 levels. Depletion of Suv39h1 reduces H3K9me3 levels, restores DNA repair capacity and delays senescence in progeroid cells.

Author(s): 
Liu, Baohua
Wang, Zimei
Zhang, Le
Ghosh, Shrestha
Zheng, Huiling
Zhou, Zhongjun
Publication Title: 
FEBS letters

Caloric restriction (CR) is known to promote longevity in various species. Sirtuin-mediated deacetylation has been shown to be related to the promotion of longevity in some species. Here, we show that CR of rats led to an increase in the level of Werner syndrome protein (WRN), a recognized DNA repair protein. In addition, CR simultaneously increased the level of SIRT1, a mammalian sirtuin. In HEK293T cells, sirtuin inhibitors decreased the WRN level, and this effect was suppressed by proteasomal inhibitors. Furthermore, we found a decrease in the WRN level in Sirt1-deficient mice.

Author(s): 
Kahyo, Tomoaki
Mostoslavsky, Raul
Goto, Makoto
Setou, Mitsutoshi
Publication Title: 
Proceedings of the National Academy of Sciences of the United States of America

Telomerase is a ribonucleoprotein reverse transcriptase that synthesizes telomeric DNA. A pseudoknot structure is phylogenetically conserved within the RNA component of telomerase in all ciliated protozoans examined. Here, we report that disruptions of the pseudoknot base pairing within the telomerase RNA from Tetrahymena thermophila prevent the stable assembly in vivo of an active telomerase. Restoring the base-pairing potential of the pseudoknot by compensatory changes restores telomerase activity to essentially wild-type levels.

Author(s): 
Gilley, D.
Blackburn, E. H.
Publication Title: 
Proceedings of the National Academy of Sciences of the United States of America

The transsulfuration pathway converts homocysteine to cysteine and represents the metabolic link between antioxidant and methylation metabolism. The first and committing step in this pathway is catalyzed by cystathionine beta-synthase (CBS), which is subject to complex regulation, including allosteric activation by the methyl donor, S-adenosylmethionine (AdoMet).

Author(s): 
Prudova, Anna
Bauman, Zachary
Braun, Aaron
Vitvitsky, Victor
Lu, Shelly C.
Banerjee, Ruma
Publication Title: 
Journal of Bacteriology

Purine nucleoside phosphorylase (PNP) is an important enzyme in purine metabolism and cleaves purine nucleosides to their respective bases. Mycobacterial PNP is specific for 6-oxopurines and cannot account for the adenosine (Ado) cleavage activity that has been detected in M. tuberculosis and M. smegmatis cultures. In the current work, two Ado cleavage activities were identified from M. smegmatis cell extracts. The first activity was biochemically determined to be a phosphorylase that could reversibly catalyze adenosine + phosphate ↔ adenine + alpha-D-ribose-1-phosphate.

Author(s): 
Buckoreelall, Kajal
Wilson, Landon
Parker, William B.
Publication Title: 
FEBS letters

Caloric restriction (CR) is known to promote longevity in various species. Sirtuin-mediated deacetylation has been shown to be related to the promotion of longevity in some species. Here, we show that CR of rats led to an increase in the level of Werner syndrome protein (WRN), a recognized DNA repair protein. In addition, CR simultaneously increased the level of SIRT1, a mammalian sirtuin. In HEK293T cells, sirtuin inhibitors decreased the WRN level, and this effect was suppressed by proteasomal inhibitors. Furthermore, we found a decrease in the WRN level in Sirt1-deficient mice.

Author(s): 
Kahyo, Tomoaki
Mostoslavsky, Raul
Goto, Makoto
Setou, Mitsutoshi
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