Disease relevance of C05431

• Biosynthesis of carotenoids derived from neurosporene in Rhodopseudomonas capsulata [1].
• Approximately 10% of known phytoene desaturases, as in Rhodobacter, produce neurosporene, whereas the rest produce lycopene [2].
• In Rb. sphaeroides, the completion of four desaturations to lycopene by the Erwinia CrtI appears to require the absence of CrtC and, in a crtC background, even the native 3-step enzyme can synthesize a significant amount (13%) of lycopene, in addition to the expected neurosporene [3].
• To test whether Sll0254 serves as a lycopene cyclase in Synechocystis, the corresponding gene was expressed in Escherichia coli strains that can produce lycopene or neurosporene [4].

High impact information on C05431

• Here we used directed evolution to change the product of Rhodobacter sphaeroides phytoene desaturase (crtI gene product), a neurosporene-producing enzyme, to lycopene [2].
• To determine whether Slr1293 is a desaturase recognizing neurosporene and lycopene, slr1293 was expressed in Escherichia coli strains accumulating neurosporene or lycopene [5].
• Furthermore, as Slr1293 appears to recognize neurosporene and to catalyze the first committed step on the myxoxanthophyll biosynthesis pathway, Slr1293 plays a pivotal role in directing a portion of the precursor pool for carotenoid biosynthesis toward myxoxanthophyll biosynthesis in Synechocystis sp. strain PCC 6803 [5].
• Escherichia coli cells transformed with several carotenogenic genes to mediate the formation of zeta-carotene, neurosporene, lycopene, beta-carotene, and zeaxanthin were exposed to UV-B radiation [6].
• Short-term kinetics revealed that endogenous levels of neurosporene and beta-carotene protected E. coli against irradiation with UV-B [6].

Chemical compound and disease context of C05431

• Two carotenoids, neurosporene and spheroidene, have been successfully added to chromatophores from the carotenoidless mutant of Rhodopseudomonas sphaeroides R26 [7].

Biological context of C05431

• When complete ripening was reached, a block occurred at the cyclization level causing the accumulation of both all-trans (i.e. gamma-carotene and neurosporene) and cis-isomer (i.e. lycopene and zeta-carotene) carotene precursors [8].
• The resonance Raman spectrum of carotenoids as an intrinsic probe for membrane potential. Oscillatory changes in the spectrum of neurosporene in the chromatophores of Rhodopseudomonas sphaeroides [9].
• The S(1)-mediated carotenoid-to- bacteriochlorophyll energy transfer efficiencies were determined to be 96%, 84%, and 73% for neurosporene, spheroidene, and spheroidenone, respectively [10].

Associations of C05431 with other chemical compounds

• The recombinant enzyme was fully active in converting zeta-carotene into lycopene in vitro with neurosporene as an intermediate [11].
• The expected precursors of carotenoid cyclization, neurosporene and (or) lycopene, were not detected in CPTA- or nicotine-inhibited cultures [12].
• Absorption and CD spectra from several mutant and reconstituted LH1 complexes, with the carotenoid neurosporene and the precursor phytoene replacing the wild-type (WT) carotenoids, are also examined [13].
• When the subsequent genes from E. uredovora which encode for lycopene cyclase and beta-carotene hydroxylase were present, neurosporene, the phytoene desaturase product of R. capsulatus, was subsequently converted to the monocyclic beta-zeacarotene and its monohydroxylation product [14].

Gene context of C05431

• The complete crtI gene has been overexpressed in Escherichia coli and R. sphaeroides and shown to catalyze three desaturations of phytoene to give neurosporene [15].

References