Editing Disulfide (section)

====Disulfides in regulatory proteins====<!--mention [[Gliotoxin]]-->
As disulfide bonds can be reversibly reduced and re-oxidized, the redox state of these bonds has evolved into a signaling element. In [[chloroplasts]], for example, the enzymatic reduction of disulfide bonds has been linked to the control of numerous metabolic pathways as well as gene expression. The reductive signaling activity has been shown, thus far, to be carried by the [[Ferredoxin-thioredoxin reductase|ferredoxin-thioredoxin system]], channeling electrons from the light reactions of [[photosystem I]] to catalytically reduce disulfides in regulated proteins in a light dependent manner. In this way chloroplasts adjust the activity of key processes such as the [[Calvin-Benson cycle|Calvin–Benson cycle]], [[starch]] degradation, [[Adenosine triphosphate|ATP]] production and gene expression according to light intensity. Additionally, It has been reported that disulfides plays a significant role on redox state regulation of Two-component systems (TCSs), which could be found in certain bacteria including photogenic strain. A unique intramolecular cysteine disulfide bonds in the ATP-binding domain of SrrAB TCs found in ''Staphylococcus aureus'' is a good example of disulfides in regulatory proteins, which the redox state of SrrB molecule is controlled by cysteine disulfide bonds, leading to the modification of SrrA activity including gene regulation.<ref>{{cite journal |last1=Tiwari |first1=Nitija |last2=López-Redondo |first2=Marisa |last3=Miguel-Romero |first3=Laura |last4=Kulhankova |first4=Katarina |last5=Cahill |first5=Michael P. |last6=Tran |first6=Phuong M. |last7=Kinney |first7=Kyle J. |last8=Kilgore |first8=Samuel H. |last9=Al-Tameemi |first9=Hassan |last10=Herfst |first10=Christine A. |last11=Tuffs |first11=Stephen W. |date=19 May 2020 |title=The SrrAB two-component system regulates Staphylococcus aureus pathogenicity through redox sensitive cysteines |journal=[[Proceedings of the National Academy of Sciences]] |volume=117 |issue=20 |pages=10989–10999 |bibcode=2020PNAS..11710989T |doi=10.1073/pnas.1921307117 |pmc=7245129 |pmid=32354997 |doi-access=free |last12=Kirby |first12=John R. |last13=Boyd |first13=Jeffery M. |last14=McCormick |first14=John K. |last15=Salgado-Pabón |first15=Wilmara |last16=Marina |first16=Alberto |last17=Schlievert |first17=Patrick M. |last18=Fuentes |first18=Ernesto J.}}</ref>