Literature summary for 2.5.1.16 extracted from

Seckute, J.; McCloskey, D.E.; Thomas, H.J.; Secrist, J.A.; Pegg, A.E.; Ealick, S.E.
Binding and inhibition of human spermidine synthase by decarboxylated S-adenosylhomocysteine (2011), Protein Sci., 20, 1836-1844.

Cloned(Commentary)

Cloned (Comment)	Organism
expression of the His-tagged enzyme in Escherichia coli strain BL21(DE3)	Homo sapiens

Crystallization (Commentary)

Crystallization (Comment)	Organism
spermidine synthase in complex with inhibitor decarboxylated S-adenosylhomocysteine and substrate putrescine, hanging drop vapor diffusion method, mixing of 0.0015 ml of 14 mg/ml protein in 20 mM Tris-HCl, pH 8.0, solution with 0.0015 ml of reservoir solution containing 100 mM Tris-HCl, pH 8.4, 200 mM sodium sulfate, and 20% w/v PEG 3350, 5 mM putrescine and 5 mM decarboxylated S-adenosylhomocysteine, 22°C, X-ray diffraction structure determmination and analysis at 2.0 A resolution	Homo sapiens

Crystallization (Comment)

Organism

spermidine synthase in complex with inhibitor decarboxylated S-adenosylhomocysteine and substrate putrescine, hanging drop vapor diffusion method, mixing of 0.0015 ml of 14 mg/ml protein in 20 mM Tris-HCl, pH 8.0, solution with 0.0015 ml of reservoir solution containing 100 mM Tris-HCl, pH 8.4, 200 mM sodium sulfate, and 20% w/v PEG 3350, 5 mM putrescine and 5 mM decarboxylated S-adenosylhomocysteine, 22°C, X-ray diffraction structure determmination and analysis at 2.0 A resolution

Homo sapiens

Inhibitors

Inhibitors	Comment	Organism
decarboxylated S-adenosylhomocysteine	active site binding structure, overview	Homo sapiens
decarboxylated S-adenosylhomocysteine	-	Plasmodium falciparum
decarboxylated S-adenosylhomocysteine	-	Thermotoga maritima

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.
S-adenosylmethioninamine + putrescine	Plasmodium falciparum	-	S-methyl-5'-thioadenosine + spermidine	-	?
S-adenosylmethioninamine + putrescine	Thermotoga maritima	-	S-methyl-5'-thioadenosine + spermidine	-	?
S-adenosylmethioninamine + putrescine	Homo sapiens	-	S-methyl-5'-thioadenosine + spermidine	-	?

Organism

Organism	UniProt	Comment	Textmining
Homo sapiens	P19623	-	-
Plasmodium falciparum	-	-	-
Thermotoga maritima	-	-	-

Reaction

Reaction	Comment	Organism	Reaction ID
S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine	this mechanism depends on a conserved Asp (residue 173 in hSpdS) in the active site that interacts with the bound amine substrate to deprotonate the attacking nitrogen atom of the amine. This interaction is reinforced by additional interactions of this nitrogen atom with the hydroxyl group of a conserved Tyr (residue 79 in hSpdS) and a backbone carbonyl group (Ser174 in hSpdS). These interactions allow the attack on the methylene carbon atom of the aminopropyl group attached to the sulfonium center of dcAdoMet. Electron transfer to this sulfur atom completes the reaction forming S-methyl-5'-thioadenosine and the polyamine product. The positively charged sulfonium ion is a critical part of the reaction	Homo sapiens	a

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
S-adenosylmethioninamine + putrescine	-	Plasmodium falciparum	S-methyl-5'-thioadenosine + spermidine	-	?
S-adenosylmethioninamine + putrescine	-	Thermotoga maritima	S-methyl-5'-thioadenosine + spermidine	-	?
S-adenosylmethioninamine + putrescine	-	Homo sapiens	S-methyl-5'-thioadenosine + spermidine	-	?

Synonyms

Synonyms	Comment	Organism
SPDS	-	Plasmodium falciparum
SPDS	-	Thermotoga maritima
SPDS	-	Homo sapiens

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
25	-	assay at	Plasmodium falciparum
25	-	assay at	Thermotoga maritima
25	-	assay at	Homo sapiens

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
8	-	assay at	Plasmodium falciparum
8	-	assay at	Thermotoga maritima
8	-	assay at	Homo sapiens