Literature summary for 3.6.1.1 extracted from

Li, W.; Meng, D.; Gu, Z.; Yang, Q.; Yuan, H.; Li, Y.; Chen, Q.; Yu, J.; Liu, C.; Li, T.
Apple S-RNase triggers inhibition of tRNA aminoacylation by interacting with a soluble inorganic pyrophosphatase in growing self-pollen tubes invitro (2018), New Phytol., 218, 579-593 .

Cloned(Commentary)

Cloned (Comment)	Organism
MdPPa is transiently expressed in Malus domestica cv. Ralls Janet pollen as GFP fusion protein driven by the tomato pollen-specific promoter Lat52, the MdPPa-GFP constructis transformed into pollen by particle bombardment. Recombinant transient expression of coding sequences (CDSs) of MdPPa and S1-, S2-, S3- and S9-RNase from pEZS-NL vector driven by CaMV 35S promoter in Zea mays protoplasts. Recombinant coexpression of MBP-tagged S1, S2, S3, S9-RNase and His6-tagged A14 in Escherichia coli	Malus domestica

Cloned (Comment)

Organism

MdPPa is transiently expressed in Malus domestica cv. Ralls Janet pollen as GFP fusion protein driven by the tomato pollen-specific promoter Lat52, the MdPPa-GFP constructis transformed into pollen by particle bombardment. Recombinant transient expression of coding sequences (CDSs) of MdPPa and S1-, S2-, S3- and S9-RNase from pEZS-NL vector driven by CaMV 35S promoter in Zea mays protoplasts. Recombinant coexpression of MBP-tagged S1, S2, S3, S9-RNase and His6-tagged A14 in Escherichia coli

Malus domestica

Inhibitors

Inhibitors	Comment	Organism	Structure
additional information	apple S-RNase binds to two variable regions of MdPPa, resulting in a noncompetitive inhibition of its activity	Malus domestica

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining
cytosol	-	Malus domestica	5829	-
soluble	MdPPa protein is detected only in the soluble fraction of pollen	Malus domestica	-	-

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
diphosphate + H2O	Malus domestica	-	2 phosphate	-	?
additional information	Malus domestica	apple soluble inorganic diphosphatase physically interacts with S-RNases, interaction analysis by pulldown assay with recombinant MBP-tagged S1, S2, S3, S9-RNase and His6-tagged A14 expressed from Escherichia coli, overview	?	-	-

Organism

Organism	UniProt	Comment	Textmining
Malus domestica	XM_008360526	cvs. Ralls Janet (S1S2), Fuji (S1S9), and Golden Delicious (S2S3)	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant MBP-tagged S1, S2, S3, S9-RNase and His6-tagged A14 from Escherichia coli and pulldown assay	Malus domestica

Source Tissue

Source Tissue	Comment	Organism	Textmining
additional information	quantitative RT-PCR expression analysis shows that MdPPa has significantly higher expression in pollen grains and pollen tubes than in other tissues	Malus domestica	-
pollen	pollen grains and pollen tubes	Malus domestica	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
diphosphate + H2O	-	Malus domestica	2 phosphate	-	?
additional information	apple soluble inorganic diphosphatase physically interacts with S-RNases, interaction analysis by pulldown assay with recombinant MBP-tagged S1, S2, S3, S9-RNase and His6-tagged A14 expressed from Escherichia coli, overview	Malus domestica	?	-	-

Synonyms

Synonyms	Comment	Organism
inorganic pyrophosphatase	-	Malus domestica
MdPPa	-	Malus domestica
soluble inorganic pyrophosphatase	-	Malus domestica
sPPAse	-	Malus domestica

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
37	-	assay at	Malus domestica

General Information

General Information	Comment	Organism
malfunction	when treated with self S-RNases, apple pollen tubes show a marked growth inhibition, as well as a decrease in endogenous soluble diphosphatase activity and elevated levels of inorganic diphosphate. In addition, S-RNase is found to bind to two variable regions of MdPPa, resulting in a noncompetitive inhibition of its activity. Silencing of MdPPa expression leads to a reduction in pollen tube growth. tRNA aminoacylation is inhibited in self S-RNase-treated or MdPPa-silenced pollen tubes, resulting in the accumulation of uncharged tRNA, but this disturbance of tRNA aminoacylation is independent of RNase activity. Excess diphosphate causes uncharged tRNA accumulation in pollen tubes	Malus domestica
physiological function	SRNase is necessary and sufficient for the pistil to reject self-pollen. S-RNase causes a decrease in sPPase activity and diphosphate accumulation in self-pollen tubes	Malus domestica