The nonlinear cysteine redox dynamics in the i-space: A proteoform-centric theory of redox regulation
The post-translational redox regulation of protein function by cysteine oxidation controls diverse biological processes, from cell division to death. However, most current site-centric paradigms fail to capture the nonlinear and emergent nature of redox regulation in proteins with multiple cysteines...
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Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Elsevier
2025-04-01
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Series: | Redox Biology |
Subjects: | |
Online Access: | http://www.sciencedirect.com/science/article/pii/S2213231725000369 |
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Summary: | The post-translational redox regulation of protein function by cysteine oxidation controls diverse biological processes, from cell division to death. However, most current site-centric paradigms fail to capture the nonlinear and emergent nature of redox regulation in proteins with multiple cysteines. Here, we present a proteoform-centric theory of redox regulation grounded in the i-space. The i-space encapsulates the theoretical landscape of all possible cysteine proteoforms. Using computational approaches, we quantify the vast size of the abstract i-space, revealing its scale-free architecture—elucidating the disproportionate influence of cysteine-rich proteins. We define mathematical rules governing cysteine proteoform dynamics. Their dynamics are inherently nonlinear, context-dependent, and fundamentally constrained by protein copy numbers. Monte Carlo simulations of the human protein PTP1B reveal extensive i-space sampling beyond site-centric models, supporting the “oxiform conjecture”. This conjecture posits that highly oxidised proteoforms, molecules bearing multiple oxidised cysteines, are central to redox regulation. In support, even 90%-reduced proteomes can house vast numbers of unique, potentially functioanlly diverse, oxiforms. This framework offers a transformative lens for understanding the redox biology of proteoforms. |
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ISSN: | 2213-2317 |