PXD074470

PXD074470 is an original dataset announced via ProteomeXchange.

Title	Magnesium as a Conformational Gatekeeper of KRAS: Structural Dynamics and Therapeutic Implications
Description	Magnesium serves as an essential cofactor for small GTPases, yet its structural role in regulating KRAS conformational dynamics and nucleotide exchange remains poorly understood. Here, we combine hydrogen–deuterium exchange mass spectrometry (HDX-MS), native mass spectrometry, and functional assays to elucidate how Mg²⁺ stabilizes the KRAS conformational ensemble and constrains transitions between GDP- and GTP-bound states. Mg²⁺ removal triggers widespread increases in structural dynamics throughout KRAS—spanning the p-loop, α1-helix, switch I, nucleotide-binding region, and distal helices—revealing a global loosening of the protein fold that favors an open, nucleotide exchange-competent state. Mg²⁺ titration experiments demonstrate that individual structural elements exhibit distinct Mg²⁺ dependencies: the p-loop and α1-helix recover native dynamics at micromolar concentrations, whereas switch I requires millimolar levels, underscoring its exceptionally high sensitivity to Mg²⁺ for structural stabilization. KRAS bound to the catalytic domain of exchange factor SOS1 displays an HDX signature closely resembling the Mg²⁺-free state, indicating that SOS1 promotes nucleotide exchange by transiently perturbing Mg²⁺ coordination while simultaneously stabilizing switch I. Consistently, phosphomimetic KRAS S17E variant, which disrupts a critical Mg²⁺-coordinating residue, exhibits pronounced global destabilization—reinforcing the central importance of Mg²⁺ in maintaining structural integrity. Taken together our findings show that Mg²⁺ acts as a master regulator of KRAS structural dynamics and reveal Mg²⁺-sensitive hotspots that might represent promising targets for next-generation KRAS therapeutics.
HostingRepository	PRIDE
AnnounceDate	2026-06-29
AnnouncementXML	Submission_2026-06-28_16:26:37.012.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Thomas Wales
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: NEWT:9606;
ModificationList	No PTMs are included in the dataset
Instrument	Synapt MS

Revision	Datetime	Status	ChangeLog Entry
0	2026-02-13 18:34:40	ID requested
⏵ 1	2026-06-28 16:26:37	announced

10.1002/pro.70681;

Srinivasu BY, Damerla TS, Stec A, Zhou Z, Engen JR, Westover KD, Wales TE, Magnesium as a conformational gatekeeper of KRAS: Structural dynamics and therapeutic implications. Protein Sci, 35(7):e70681(2026) [pubmed]

submitter keyword: KRAS

allostery

HDX-MS

hydrogen/deuterium exchange mass spectrometry

Thomas E. Wales
contact affiliation	Northeastern UNiversity
contact email	t.wales@northeastern.edu
lab head
Thomas Wales
contact affiliation	Northeastern University
contact email	t.wales@northeastern.edu
dataset submitter

Dataset FTP location NOTE: Most web browsers have now discontinued native support for FTP access within the browser window. But you can usually install another FTP app (we recommend FileZilla) and configure your browser to launch the external application when you click on this FTP link. Or otherwise, launch an app that supports FTP (like FileZilla) and use this address: ftp://ftp.pride.ebi.ac.uk/pride/data/archive/2026/06/PXD074470

PRIDE project URI

• PRIDE
  1. PXD074470
     1. Label: PRIDE project
     2. Name: Magnesium as a Conformational Gatekeeper of KRAS: Structural Dynamics and Therapeutic Implications