The Active Principle of Garlic at Atomic Resolution

Kuettner, E.B.; Hilgenfeld, Rolf; Weiss, M.S.

doi:10.1074/jbc.m208669200

Cited by 66 publications

(72 citation statements)

References 28 publications

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“…S3). Further, structural studies show that the garlic alliinase is very similar to aminotransferases (Kuettner et al, 2002). Together with the earlier studies of Stepanova et al (2008) and Tao et al (2008), our analysis indicates that TIR2 is a Trp aminotransferase that synthesizes IPA from Trp (Fig.…”

Section: Tir2 Is Required For Diverse Auxin-dependent Processes In Thsupporting

confidence: 83%

“…S1B). The function of alliinase has previously been characterized in garlic and onion (Allium cepa; Kuettner et al, 2002). This enzyme catalyzes the conversion of a specific nonprotein sulfur-containing amino acid called alliin to allicin, a compound with antibiotic activity.…”

Section: Tir2 Is Required For Diverse Auxin-dependent Processes In Thmentioning

confidence: 99%

“…In the tir2-1 allele, Gly-171 is changed to Glu. This residue is conserved among all members of the alliinase/transaminase family and is part of the so-called strained loop involved in pyridoxal phosphate cofactor binding (Kuettner et al, 2002). It is likely that substitution of Glu at this position would disrupt this structure and pyridoxal phosphate binding.…”

Section: Tir2 Is Required For the Ipa Pathwaymentioning

confidence: 99%

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TheTRANSPORT INHIBITOR RESPONSE2Gene Is Required for Auxin Synthesis and Diverse Aspects of Plant Development

et al. 2009

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The plant hormone auxin plays an essential role in plant development. However, only a few auxin biosynthetic genes have been isolated and characterized. Here, we show that the TRANSPORT INHIBITOR RESPONSE2 (TIR2) gene is required for many growth processes. Our studies indicate that the tir2 mutant is hypersensitive to 5-methyl-tryptophan, an inhibitor of tryptophan synthesis. Further, treatment with the proposed auxin biosynthetic intermediate indole-3-pyruvic acid (IPA) and indole-3-acetic acid rescues the tir2 short hypocotyl phenotype, suggesting that tir2 may be affected in the IPA auxin biosynthetic pathway. Molecular characterization revealed that TIR2 is identical to the TAA1 gene encoding a tryptophan aminotransferase. We show that TIR2 is regulated by temperature and is required for temperature-dependent hypocotyl elongation. Further, we find that expression of TIR2 is induced on the lower side of a gravitropically responding root. We propose that TIR2 contributes to a positive regulatory loop required for root gravitropism.

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Section: Tir2 Is Required For Diverse Auxin-dependent Processes In Thsupporting

confidence: 83%

Section: Tir2 Is Required For Diverse Auxin-dependent Processes In Thmentioning

confidence: 99%

Section: Tir2 Is Required For the Ipa Pathwaymentioning

confidence: 99%

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TheTRANSPORT INHIBITOR RESPONSE2Gene Is Required for Auxin Synthesis and Diverse Aspects of Plant Development

et al. 2009

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“…Previous amino-acid sequence analysis revealed 10 cysteine residues per alliinase subunit, 2 and X-ray crystal structure showed that six of these cysteine residues form three adjacent disulfide bridges at the N-terminal part of the alliinase subunit. 4,6 In the present study, we examined the configuration and reactivity of the remaining four cysteine residues and demonstrated that two free thiols are located far from the active site of the enzyme, and their modification does not affect the enzyme's structure and activity. Cys368 and Cys376 form a SAS bridge located close to C-terminus and has a role in maintaining both the rigidity of the catalytic domain and the substrate-cofactor relative orientation.…”

Section: Introductionmentioning

confidence: 80%

“…[3][4][5][6] The enzyme is a homodimeric glycoprotein belonging to the fold-type I family of PLP-dependent enzymes. Allicin, a product of the enzymatic reaction of alliinase with alliin, is the well-characterized, biologically active compound of garlic.…”

Section: Introductionmentioning

confidence: 99%

Thiol‐disulfide organization in alliin lyase (alliinase) from garlic (Allium sativum)

et al. 2008

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Alliinase, an enzyme found in garlic, catalyzes the synthesis of the well-known chemically and therapeutically active compound allicin (diallyl thiosulfinate). The enzyme is a homodimeric glycoprotein that belongs to the fold-type I family of pyridoxal-5 0 -phosphate-dependent enzymes. There are 10 cysteine residues per alliinase monomer, eight of which form four disulfide bridges and two are free thiols. Cys368 and Cys376 form a SAS bridge located near the C-terminal and plays an important role in maintaining both the rigidity of the catalytic domain and the substrate-cofactor relative orientation. We demonstrated here that the chemical modification of allinase with the colored ASH reagent N-(4-dimethylamino-3,5-dinitrophenyl) maleimide yielded chromophore-bearing peptides and showed that the Cys220 and Cys350 thiol groups are accesible in solution. Moreover, electron paramagnetic resonance kinetic measurements using disulfide containing a stable nitroxyl biradical showed that the accessibilities of the two ASH groups in Cys220 and Cys350 differ. Neither enzyme activity nor protein structure (measured by circular dichroism) were affected by the chemical modification of the free thiols, indicating that alliinase activity does not require free ASH groups. This allowed the oriented conjugation of alliinase, via the ASH groups, with low-or high-molecular-weight molecules as we showed here. Modification of the alliinase thiols with biotin and their subsequent binding to immobilized streptavidin enabled the efficient enzymatic production of allicin.

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The Biosynthesis of Volatile Sulfur Flavour Compounds

Jones¹

2010

The Chemistry and Biology of Volatiles

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Many natural biological flavours are products of secondary metabolism and pose a particular challenge in understanding both their biosynthetic pathways and roles within their native organism. The concepts of primary and secondary metabolism were adopted at the end of the nineteenth century to distinguish the pathways for the biosynthesis of the essential metabolites required in all cells (e.g. amino acids, lipids, carbohydrates, nucleotides), whether plant, animal or microbial, from the metabolites that were frequently species-specific and initially considered dispensable (e.g. isoprenoids, phenolics, steroids). These definitions have inevitably become looser as knowledge of metabolism and genetics has advanced and demonstrate both complexity and conservation in biosynthetic pathways for secondary metabolites. The biosynthesis of secondary metabolites is now seen as the result of a highly organized and controlled process, frequently requiring large numbers of enzymes and complex genetic regulation. Furthermore, many secondary metabolites are now known to be essential for survival. 1 The early appreciation that secondary metabolites are usually restricted to a particular species has remained true. In contrast to the substantial uniformity of primary metabolism, secondary metabolism is frequently species-and indeed cell type-specific and understanding their biosynthesis requires research within the specific producer organisms. The model organism approach, which proved so powerful in advancing biological knowledge during the late twentieth century, therefore has limited value because the

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The Active Principle of Garlic at Atomic Resolution

Cited by 66 publications

References 28 publications

TheTRANSPORT INHIBITOR RESPONSE2Gene Is Required for Auxin Synthesis and Diverse Aspects of Plant Development

TheTRANSPORT INHIBITOR RESPONSE2Gene Is Required for Auxin Synthesis and Diverse Aspects of Plant Development

Thiol‐disulfide organization in alliin lyase (alliinase) from garlic (Allium sativum)

The Biosynthesis of Volatile Sulfur Flavour Compounds

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