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Literature summary for 3.6.5.4 extracted from

  • Shen, K.; Wang, Y.; Hwang Fu, Y.H.; Zhang, Q.; Feigon, J.; Shan, S.O.
    Molecular mechanism of GTPase activation at the signal recognition particle (SRP) RNA distal end (2013), J. Biol. Chem., 288, 36385-36397.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 3.6.5.4

Activating Compound

Activating Compound Comment Organism Structure
signal recognition particle RNA SRP RNA, the signal recognition particle RNA distal end triggers GTP hydrolysis in the signal recognition particle protein-SRP receptor GTPase, i.e. Ffh-FtsY GTPase, complex. An intact docking site at the distal end of SRP RNA is required to stimulate GTPase activation. Loop E plays a crucial role in GTPase activation by the SRP RNA Escherichia coli

Protein Variants

Protein Variants Comment Organism
C86A mutations at C86 yield a more complex pattern: whereas C86A and C86U completely abolish GTPase activation by the RNA, C86 and C86G reduce GTPase activity by only 50% Escherichia coli
C86G mutations at C86 yield a more complex pattern: whereas C86A and C86U completely abolish GTPase activation by the RNA, DELTAC86 and C86G reduce GTPase activity by only 50%. Despite defective GTP hydrolysis, the G83A mutant shows any detectable defect in the efficiency of GTPase docking at the distal end Escherichia coli
C86U mutations at C86 yield a more complex pattern: whereas C86A and C86U completely abolish GTPase activation by the RNA, C86 and C86G reduce GTPase activity by only 50% Escherichia coli
C87A/C97U site-directed mutagenesis, combining C97U with C87A generates a superactive SRP RNA double mutant that hydrolyzes GTP 5.5fold faster than wild-type SRP RNA Escherichia coli
C97U site-directed mutagenesis, the mutant prolongs GTPase docking at the distal end, which correlates with its faster GTP hydrolysis rate Escherichia coli
C97U/G99A site-directed mutagenesis, combining G99A with C87A generate s a superactive SRP RNA double mutant that hydrolyzes GTP 4.6fold faster than wild-type SRP RNA Escherichia coli
G83A deletion or substitution of G83 by any other nucleotide completely abolishes the stimulatory effect of the SRP RNA on GTP hydrolysis. Despite defective GTP hydrolysis, the G83A mutant shows any detectable defect in the efficiency of GTPase docking at the distal end Escherichia coli
G99A site-directed mutagenesis, the mutant prolongs GTPase docking at the distal end, which correlates with its faster GTP hydrolysis rate Escherichia coli
additional information several mutants show higher GTPase activity than wild-type SRP RNA, most notably mutations at G99, U12, and C97. By modifying the GTPase docking interface, the efficiency of activation of the Ffh-FtsY GTPase complex can be specifically tuned. When G83 is mutated, substitution of C86 with guanine rescues the SRP RNA-mediated stimulation of GTPase activity to 50% of wild-type rate. Despite defective GTP hydrolysis, neither the G83A nor C86G mutant shows any detectable defect in the efficiency of GTPase docking at the distal end Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
GTP + H2O Escherichia coli
-
 GDP + phosphate
-
 ?

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
GTP + H2O
-
 Escherichia coli GDP + phosphate
-
 ?
GTP + H2O conserved bases in loop D specifically catalyze GTP hydrolysis, a guanine at residue 86 can compete with and substitute for G83 as a catalytic base, loop E controls the action of the distal end docking sites Escherichia coli GDP + phosphate
-
 ?

Synonyms

Synonyms Comment Organism
SRP receptor GTPase
-
 Escherichia coli

General Information

General Information Comment Organism
metabolism in prokaryotic cells, the signal recognition particle consists of a SRP54 protein or Ffh and a 4.5S SRP RNA. Ffh contains a methionine-rich M domain, which binds the SRP RNA and the signal sequence on the translating ribosome. In addition, an NG domain in Ffh, comprising a GTPase G domain and a four-helix bundle N domain, forms a tight complex with a highly homologous NG domain in the SRP receptor, called FtsY in bacteria, in the presence of GTP. GTP hydrolysis at the end of the signal recognition particle cycle drives the disassembly of the Ffh-FtsY GTPase complex. The assembly of the signal recognition particle-FtsY GTPase complex and its GTPase activation require discrete conformational rearrangements in the signal recognition particle that are regulated by the RNC and the target membrane, respectively, thus ensuring the spatial and temporal precision of these molecular events during protein targeting, function of SRP RNA during co-translational protein targeting, overiew Escherichia coli
additional information bidentate interaction between the Ffh-FtsY GTPase complex and the distal end of the SRP RNA, overview. By modifying the GTPase docking interface, the efficiency of activation of the Ffh-FtsY GTPase complex can be specifically tuned. A guanine at residue 86 could compete with and substitute for G83 as a catalytic base. Conserved bases in loop D specifically catalyze GTP hydrolysis, a guanine at residue 86 can compete with and substitute for G83 as a catalytic base, loop E controls the action of the distal end docking sites Escherichia coli
physiological function the enzyme is involved in translocation of the signal recognition particle (SRP) RNA is a universally conserved and essential component of the SRP that mediates the co-translational targeting of proteins to the correct cellular membrane. During the targeting reaction, two functional ends in the signal recognition particle RNA mediate distinct functions. Whereas the RNA tetraloop facilitates initial assembly of two GTPases between the signal recognition particle and signal recognition particle receptor, this GTPase complex subsequently relocalizes about 100 A to the 5',3'-distal end of the RNA, a conformation crucial for GTPase activation and cargo handover Escherichia coli