A new pteridine glycoside, called cyanopterin, was isolated from Synechocystis sp. PCC 6803 and its structure was elucidated as 6-[1-(4-O-methyl-(α-D-glucuronyl)-(1,6)-(β-D-galactosyloxy]methylpterin by chemical degradation and 1H- and 13C-NMR spectroscopic means. Cyanopterin is constitutively synthesized at a relatively high intracellular concentration that is comparable to that of chlorophyll a in a molar ratio of approximately 1 to 1.6. The in vivo oxidation state of cyanopterin is primarily the fully reduced 5,6,7,8-tetrahydro form. The cellular function is unknown at present. The findings have established a model system, using Synechocystis sp. PCC 6803, for studies of the physiological functions of unconjugated pteridine glycosides found mostly in cyanobacteria.

cyanopterin, 6-hydroxymethylpterin glycoside, Synechocystis sp. PCC 6803

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7
6,6,4	Me	61.91
6,6	aDGlcpA	99.90	72.29	74.02	83.09	71.02	174.58
6	bDGalp	104.47	72.40	74.20	70.48	75.14	69.20
	Subst	153.10	161.35	128.21	153.58	151.37	148.23	70.79


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7
6,6,4	Me	3.47
6,6	aDGlcpA	4.96	3.65	3.77	3.32	4.19	-
6	bDGalp	4.62	3.63	3.70	3.97	3.92	3.74-3.88
	Subst	-	-	-	-	8.99	-	5.05-5.20


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7
6,6,4	Me	61.91/3.47
6,6	aDGlcpA	99.90/4.96	72.29/3.65	74.02/3.77	83.09/3.32	71.02/4.19	
6	bDGalp	104.47/4.62	72.40/3.63	74.20/3.70	70.48/3.97	75.14/3.92	69.20/3.74-3.88
	Subst					151.37/8.99		70.79/5.05-5.20

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CO[C@@H]1[C@@H](C(=O)O)O[C@H](OC[C@H]2O[C@@H](OCc3cnc4nc(N)[nH]c(=O)c4n3)[C@H](O)[C@@H](O)[C@H]2O)[C@H](O)[C@H]1O

545.458 g/mol (C₂₀H₂₇N₅O₁₃)

A new pteridine compound was isolated from green sulfur photosynthetic bacteria, Chlorobium limicola f. thiosulfatophilum NCIB 8327. The structure of this pterin derivative was established to be 1-O-(L-erythro-5,6,7,8- tetrahydropterin-2′-yl)-β-N-acetylglucosamine (1) from 1H-NMR and CD spectra as well as from various mass spectrometric techniques and chemical-cleavage techniques. Upon acid hydrolysis of 1, equimolar amounts of biopterin (2) and N-acetylglucosamine were produced. The structure of the hydrolysis product 2 was confirmed by comparing its NMR, UV, CD, and MS and its chromatographical behavior with those of an authentic specimen. N-Acetylglucosamine was identified by an enzymatic hydrolysis experiment as well as by NMR and thin layer chromatography. Electrospray (ES), fast-atom-bombardment (FAB), and thermospray (TS) mass spectrometry of 1 yielded an MH+ at m/z 441. Periodate-oxidation experiments of the intact molecule 1 and of its hydrolysis product 2 are consistent with the proposed structure. Differential I2 oxidation experiments with the native compound showed that the in vivo oxidation state of this pterin is its tetrahydro form. We propose the trivial name ‘limipterin’ for this new compound.

pteridine, Chlorobium limicola, limipterin, green sulfur bacteria

13C NMR data:
missing...
1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8	H9
12,2	Ac	-	1.77
12	bDGlcpN	4.56	3.50	3.41	3.35	3.90	3.41-3.71
	Subst	-	-	-	8.74	-	-	4.76	4.28	1.33

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CC(=O)N[C@H]1[C@H](O[C@@H](C)[C@H](O)c2cnc3nc(N)[nH]c(=O)c3n2)O[C@H](CO)[C@@H](O)[C@@H]1O

440.413 g/mol (C₁₇H₂₄N₆O₈)

A novel pterin compound, designated as tepidopterin, was detected from a thermophilic photosynthetic green sulphur bacterium, Chlorobium tepidum. The amount of tepidopterin inside the cell was estimated to be 2-5 μmol/g dry weight of cell. This compound was purified through a high performance liquid chromatography using preparative ∆Pak C18 column. This compound was characterized by chromatographic behavior and by absorption and fluorescence properties. Its structure was determined to be 1-O-(L-threo-biopterin-2'-yl)-β-N-acetylglucosamine by 1D- and 2D-NMR spectroscopy, mass spectrometry and CD. The relative amount of tetrahydrotepidopterin was estimated to be 96.7% inside the cell, that of dihydrotepidopterin 2.9%, and that of fully oxidized tepidopterin 0.4%. The amount of tepidopterin within the cell increased continuously until the beginning of the stationary phase of the cell growth.

N-acetylglucosamine, tepidopterin, L-threo-biopterin, Chlorobium tepidum

1H NMR data:
missing...

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CC(=O)N[C@H]1[C@H](O[C@@H](C)[C@@H](O)c2cnc3[nH]c(N)nc(=O)c3n2)O[C@H](CO)[C@@H](O)[C@@H]1O

440.413 g/mol (C₁₇H₂₄N₆O₈)

A pteridine glycoside in Synechococcus sp. PCC 7942, the structure of which had been tentatively identified as biopterin-glucoside, was isolated and characterized for its exact chemical structure by 2D-NMR spectroscopy. The determined structure is 1-O-(L-erythro-biopterin-2'-yl)-α-glucose. It is the first report on the occurrence of a biopterin-glucoside having a alpha-configured sugar directly, attached at the pteridine ring. This result also supports that the previously purified UDP-glucose: BH4 glucosyltransferase from Synechococcus sp. PCC 7942, which catalyzes the synthesis of BH4-glucoside from UDP-glucose and BH4, is a α-glucosyltransferase.

biopterin-glucoside, tetrahydrobiopterin, pteridine glycosyltransferase

13C NMR data:
missing...

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C[C@H](O[C@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O)[C@H](O)c1cnc2nc(N)[nH]c(=O)c2n1

399.36 g/mol (C₁₅H₂₁N₅O₈)