Dataset Information

MS/MS analysis of in-gel tryptic peptides of wild-type and mutants of glutamine amidotransferase from Methanocaldococcus jannaschii

ABSTRACT: A stable post-translational modification, succinimide (SNN), found in Methanocaldococcus jannaschii (Mj) glutamine amidotransferase (GATase) is shown to impart hyper-thermostability to the protein. To explore the role of neighbouring residues in enabling deamidation of Asn109 to SNN, intact protein mass analysis on 12 mutants of MjGATase was performed. Among these mutants, 8 showed varied proportions of mass corresponding to unmodified Asn109. SNN is known to undergo rapid hydrolysis to Asp/iso-Asp, hence, this population can also exist. As Asn intact and Asp/iso-Asp populations differ by only 1 Da, ambiguity exists in their assignment. Therefore, to determine the true levels of unmodified Asn109 population, in-gel trypsin digestion followed by MS/MS analysis of the tryptic peptides for 8 mutants and wild-type of MjGATase was conducted. The MS/MS analysis of two double mutants assured that they indeed retain Asn109 intact, forming a major population. This study points toward the presence of internal catalysts that enable the deamidation of Asn109 to SNN in MjGATase.

INSTRUMENT(S):

ORGANISM(S): Methanocaldococcus Jannaschii

SUBMITTER: Hemalatha Balaram

LAB HEAD: Hemalatha Balaram

PROVIDER: PXD075155 | Pride | 2026-06-08

REPOSITORIES: pride

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Insights into the role of internal catalysts in asparagine-to-succinimide conversion in a hyperthermophilic glutamine amidotransferase.

Chandrashekarmath Anusha A Jash Oishika O Singh Karandeep K Bellur Asutosh A Roy Chitralekha Sen CS Dongre Aparna A Chathoth Nayana Edavan NE Anjukandi Padmesh P Kumar Sanjeev S Mukherjee Souradip S Balaram Padmanabhan P Balasubramanian Sundaram S Balaram Hemalatha H

The Journal of biological chemistry 20260428 6

Succinimide (SNN), an intermediate spontaneously formed during asparaginyl deamidation or aspartyl dehydration in proteins, is generally hydrolysis-prone, leading to isomerization to an L/D α/β-aspartyl residue, with the latter being considered deleterious to protein structure and function. An unusually stable SNN-mediated conformational rigidity through restriction of the backbone dihedral angle, ψ, enhances the thermostability of glutamine amidotransferase (GATase) from Methanocaldococcus jann ...[more]

PMID: 42055332

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			Action	DRS
	MjGATase_D110N_1.mgf	Mgf
	MjGATase_D110N_1.msf	Msf
	MjGATase_D110N_1.mzTab	Mztab
	MjGATase_D110N_1.pdResult	Other
	MjGATase_D110N_1.raw	Raw