The Glutamate Switch Is Present in All Seven Clades of AAA+ Protein

Abstract

Recent work has identified a "glutamate switch" in six of the seven clades of AAA+ ATPases. The glutamate switch acts to transduce information regarding substrate binding to the ATPase active site. We provide biochemical evidence that a highly conserved threonine residue acts as a glutamate switch in the replicative helicase, MCM, and, thus, reveal that the glutamate switch is a feature common to all seven AAA+ clades.

The interplay of DNA binding, ATP hydrolysis and helicase activities of the archaeal MCM helicase

“…This indicates that this mutation is defective in transducing information from the DNA binding site of the helicase to the ATPase active site. The behaviour of this mutant is superficially reminiscent of that of the T364E mutation of the glutamate switch [18,19]. The glutamate switch is a conserved residue in all clades of AAA+ ATPases that plays a key role in aligning the catalytic glutamate in the Walker B motif for activation of a water molecule during ATP hydrolysis [18,19].…”

“…The behaviour of this mutant is superficially reminiscent of that of the T364E mutation of the glutamate switch [18,19]. The glutamate switch is a conserved residue in all clades of AAA+ ATPases that plays a key role in aligning the catalytic glutamate in the Walker B motif for activation of a water molecule during ATP hydrolysis [18,19]. Like the R329E mutant, the glutamate switch mutant SsoMCM (T364E) can still bind DNA yet displays lowered helicase activity and has reduced ATPase activity that is no longer stimulated by DNA.…”

The MCM and RecQ Helicase Families: Ancient Roles in DNA Replication and Genomic Stability Lead to Distinct Roles in Human Disease

“…The MCMs require a clamp-loading factor to assemble as a multimeric ring on DNA, and this function is fulfilled in known cases by the protein Cdc6 [59][60][61][62][63][64] although the regulation of this step in the formation of the CMG complex proceeds through multiple pathways [57,58]. Various papers have dealt with the function of MCM proteins in DNA replication [10,46,[65][66][67][68], and regarding their processive mechanism of DNA unwinding [27,56,58,69,70] and only certain lingering, disease-related questions will be considered here. A summary statement can be made regarding known relationships between MCM and RecQ helicases.…”

Molecular basis of nucleotide-dependent substrate engagement and remodeling by an AAA+ activator

“…While in the ATP or ADP.AlF transition state, E108 interacts with N64, and L1 is in a dynamic released conformation, enabling it to interact with the σ 54 substrate (16). Subsequently, it was discovered that the ‘Glutamate Switch’ pair is conserved across AAA+ proteins (3,28). In addition to regulate substrate binding through nucleotide binding and hydrolysis, the ‘Glutamate Switch’ could also regulate ATP hydrolysis upon binding to its remodeling target (3).…”