1721-59-1Relevant articles and documents
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Ageta,H.,Shiojima,K.
, p. 1372 (1968)
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Characterization of Radical SAM Adenosylhopane Synthase, HpnH, which Catalyzes the 5′-Deoxyadenosyl Radical Addition to Diploptene in the Biosynthesis of C35 Bacteriohopanepolyols
Sato, Shusuke,Kudo, Fumitaka,Rohmer, Michel,Eguchi, Tadashi
supporting information, p. 237 - 241 (2019/11/28)
Adenosylhopane is a crucial intermediate in the biosynthesis of bacteriohopanepolyols, which are widespread prokaryotic membrane lipids. Herein, it is demonstrated that reconstituted HpnH, a putative radical S-adenosyl-l-methionine (SAM) enzyme, commonly encoded in the hopanoid biosynthetic gene cluster, converts diploptene into adenosylhopane in the presence of SAM, flavodoxin, flavodoxin reductase, and NADPH. NMR spectra of the enzymatic reaction product were identical to those of synthetic (22R)-adenosylhopane, indicating that HpnH catalyzes stereoselective C?C formation between C29 of diploptene and C5′ of 5′-deoxyadenosine. Further, the HpnH reaction in D2O-containing buffer revealed that a D atom was incorporated at the C22 position of adenosylhopane. Based on these results, we propose a radical addition reaction mechanism catalyzed by HpnH for the formation of the C35 bacteriohopane skeleton.
Squalene-Hopene Cyclase: Mechanistic Insights into the Polycyclization Cascades of Squalene Analogs Bearing Ethyl and Hydroxymethyl Groups at the C-2 and C-23 Positions
Kaneko, Ikki,Terasawa, Yuri,Hoshino, Tsutomu
, p. 11139 - 11157 (2018/08/03)
Squalene-hopene cyclase (SHC) catalyzes the conversion of squalene 1 into 6,6,6,6,5-fused pentacyclic hopene 2 and hopanol 3. To elucidate the binding sites for the terminal positions of 1, four analogs, having the larger ethyl (Et) and the hydrophilic CH2OH groups at the 23E or 23Z positions of 1, were incubated with SHC. The analog with the Et group at the 23E position (23E-Et-1) yielded two tetra- and three pentacyclic products; however, the analog possessing the Et group at the 23Z position (23Z-Et-1) gave two hopene homologs and the neohopane skeleton, but no hopanol homologs. Hopene homolog (C31) was generated from 23E-Et-1 by deprotonation from 23Z-Me (normal cyclization cascade). Intriguingly, the same homolog was also generated from the geometrical isomer 23Z-Et-1, indicating C?C bond rotation about the C-21?C-22 axis of the hopanyl cation and the more compact nature of the binding domain at 23Z compared with 23E. On the other hand, analogs with the CH2OH group gave novel hopane skeletons having 1-formylethyl and 1-hydroxyprop-2-en-2-yl residues at C-21. Products bearing an aldehyde group were generated in higher yield from 23Z-CH2OH-1 (89 %), than from 23E-CH2OH-1 (26 %). The significant yield (26 %) of the aldehyde products from 23E-CH2OH-1 indicated that C?C bond rotation had occurred owing to the absence of hydrophobic interactions between the hydrophilic 23E-CH2OH and its binding site. The polycyclization mechanisms of the four different analogs are discussed.
Synthesis of Heterocyclic Terpenoids by Promiscuous Squalene-Hopene Cyclases
Seitz, Miriam,Syrén, Per-Olof,Steiner, Lisa,Klebensberger, Janosch,Nestl, Bettina M.,Hauer, Bernhard
, p. 436 - 439 (2013/04/24)
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