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The multi-protein family of sulfotransferases in plants: composition, occurrence, substrate specificity, and functions.

Hirschmann F, Krause F, Papenbrock J - Front Plant Sci (2014)

Bottom Line: Arabidopsis thaliana SOTs, the best characterized SOT multi-protein family, contains 21 members.Probably, the three-dimensional structures of more plant proteins need to be solved to analyze the mode of action and the responsible amino acids for substrate binding.In addition to A. thaliana, more plant species from several families need to be investigated to fully elucidate the diversity of sulfated molecules and the way of biosynthesis catalyzed by SOT enzymes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Botany, Leibniz University Hannover Hannover, Germany.

ABSTRACT
All members of the sulfotransferase (SOT, EC 2.8.2.-) protein family transfer a sulfuryl group from the donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to an appropriate hydroxyl group of several classes of substrates. The primary structure of these enzymes is characterized by a histidine residue in the active site, defined PAPS binding sites and a longer SOT domain. Proteins with this SOT domain occur in all organisms from all three domains, usually as a multi-protein family. Arabidopsis thaliana SOTs, the best characterized SOT multi-protein family, contains 21 members. The substrates for several plant enzymes have already been identified, such as glucosinolates, brassinosteroids, jasmonates, flavonoids, and salicylic acid. Much information has been gathered on desulfo-glucosinolate (dsGl) SOTs in A. thaliana. The three cytosolic dsGl SOTs show slightly different expression patterns. The recombinant proteins reveal differences in their affinity to indolic and aliphatic dsGls. Also the respective recombinant dsGl SOTs from different A. thaliana ecotypes differ in their kinetic properties. However, determinants of substrate specificity and the exact reaction mechanism still need to be clarified. Probably, the three-dimensional structures of more plant proteins need to be solved to analyze the mode of action and the responsible amino acids for substrate binding. In addition to A. thaliana, more plant species from several families need to be investigated to fully elucidate the diversity of sulfated molecules and the way of biosynthesis catalyzed by SOT enzymes.

No MeSH data available.


Related in: MedlinePlus

Conserved regions I to IV of plant SOTs. Regions are shown as boxes, with size and position in the protein relative to the average size of SOTs from Arabidopsis thaliana. Functional amino acids were obtained from structural analyses of mouse SOTs as described above. The PAPS binding regions (5′P-motif, 3′P-motif, GxxGxxK), the proton acceptor histidine (His), and a poly-glutamic acid (Poly-Glu), that can be found in many plant SOTs, are labeled. The position of the Pfam domain PF00685 is shaded in gray.
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Figure 2: Conserved regions I to IV of plant SOTs. Regions are shown as boxes, with size and position in the protein relative to the average size of SOTs from Arabidopsis thaliana. Functional amino acids were obtained from structural analyses of mouse SOTs as described above. The PAPS binding regions (5′P-motif, 3′P-motif, GxxGxxK), the proton acceptor histidine (His), and a poly-glutamic acid (Poly-Glu), that can be found in many plant SOTs, are labeled. The position of the Pfam domain PF00685 is shaded in gray.

Mentions: Sequence alignments of eleven cytosolic SOTs from plants, animals, and bacteria resulted in the identification of four highly conserved regions I to IV (Marsolais and Varin, 1995; Figure 2). Further analyses showed that especially the regions I and IV are highly conserved, for example throughout the SOT family of A. thaliana (Klein and Papenbrock, 2004). The regions I, II, and IV are responsible for the binding of the co-substrate PAPS (Varin et al., 1997b). The first structural approach to clarify the relevance of the regions for PAPS binding was determined by X-ray crystallography analyses of a mouse estrogen SOT (Kakuta et al., 1997). Region I is localized close to the N-terminus and includes the PAPS binding domain (PSB domain) that interacts with the 5′-phosphate of PAPS. Region II starts with a characteristic highly conserved histidine, responsible for proton acceptance during the sulfuryl transfer (Kakuta et al., 1998). In the C-terminal part of region II the two amino acids Arg130 and Ser138 are responsible for the binding of the 3′-phosphate of PAP and form a 3′ P-motif (Kakuta et al., 1997). This motif can be found in 18 SOTs out of 22 from A. thaliana and from almost all other plant SOTs. In many plant SOTs, a conserved hydrophilic site containing poly-glutamic acid (Poly-Glu) of unknown function can be found between region III and IV. Similar motifs have been found in a human chondroitin 6-SOT, but at a different position (Fukuta et al., 1998). Region IV is localized at the C-terminus and contains a P-loop related GxxGxxK motif (Figure 2).


The multi-protein family of sulfotransferases in plants: composition, occurrence, substrate specificity, and functions.

Hirschmann F, Krause F, Papenbrock J - Front Plant Sci (2014)

Conserved regions I to IV of plant SOTs. Regions are shown as boxes, with size and position in the protein relative to the average size of SOTs from Arabidopsis thaliana. Functional amino acids were obtained from structural analyses of mouse SOTs as described above. The PAPS binding regions (5′P-motif, 3′P-motif, GxxGxxK), the proton acceptor histidine (His), and a poly-glutamic acid (Poly-Glu), that can be found in many plant SOTs, are labeled. The position of the Pfam domain PF00685 is shaded in gray.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4199319&req=5

Figure 2: Conserved regions I to IV of plant SOTs. Regions are shown as boxes, with size and position in the protein relative to the average size of SOTs from Arabidopsis thaliana. Functional amino acids were obtained from structural analyses of mouse SOTs as described above. The PAPS binding regions (5′P-motif, 3′P-motif, GxxGxxK), the proton acceptor histidine (His), and a poly-glutamic acid (Poly-Glu), that can be found in many plant SOTs, are labeled. The position of the Pfam domain PF00685 is shaded in gray.
Mentions: Sequence alignments of eleven cytosolic SOTs from plants, animals, and bacteria resulted in the identification of four highly conserved regions I to IV (Marsolais and Varin, 1995; Figure 2). Further analyses showed that especially the regions I and IV are highly conserved, for example throughout the SOT family of A. thaliana (Klein and Papenbrock, 2004). The regions I, II, and IV are responsible for the binding of the co-substrate PAPS (Varin et al., 1997b). The first structural approach to clarify the relevance of the regions for PAPS binding was determined by X-ray crystallography analyses of a mouse estrogen SOT (Kakuta et al., 1997). Region I is localized close to the N-terminus and includes the PAPS binding domain (PSB domain) that interacts with the 5′-phosphate of PAPS. Region II starts with a characteristic highly conserved histidine, responsible for proton acceptance during the sulfuryl transfer (Kakuta et al., 1998). In the C-terminal part of region II the two amino acids Arg130 and Ser138 are responsible for the binding of the 3′-phosphate of PAP and form a 3′ P-motif (Kakuta et al., 1997). This motif can be found in 18 SOTs out of 22 from A. thaliana and from almost all other plant SOTs. In many plant SOTs, a conserved hydrophilic site containing poly-glutamic acid (Poly-Glu) of unknown function can be found between region III and IV. Similar motifs have been found in a human chondroitin 6-SOT, but at a different position (Fukuta et al., 1998). Region IV is localized at the C-terminus and contains a P-loop related GxxGxxK motif (Figure 2).

Bottom Line: Arabidopsis thaliana SOTs, the best characterized SOT multi-protein family, contains 21 members.Probably, the three-dimensional structures of more plant proteins need to be solved to analyze the mode of action and the responsible amino acids for substrate binding.In addition to A. thaliana, more plant species from several families need to be investigated to fully elucidate the diversity of sulfated molecules and the way of biosynthesis catalyzed by SOT enzymes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Botany, Leibniz University Hannover Hannover, Germany.

ABSTRACT
All members of the sulfotransferase (SOT, EC 2.8.2.-) protein family transfer a sulfuryl group from the donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to an appropriate hydroxyl group of several classes of substrates. The primary structure of these enzymes is characterized by a histidine residue in the active site, defined PAPS binding sites and a longer SOT domain. Proteins with this SOT domain occur in all organisms from all three domains, usually as a multi-protein family. Arabidopsis thaliana SOTs, the best characterized SOT multi-protein family, contains 21 members. The substrates for several plant enzymes have already been identified, such as glucosinolates, brassinosteroids, jasmonates, flavonoids, and salicylic acid. Much information has been gathered on desulfo-glucosinolate (dsGl) SOTs in A. thaliana. The three cytosolic dsGl SOTs show slightly different expression patterns. The recombinant proteins reveal differences in their affinity to indolic and aliphatic dsGls. Also the respective recombinant dsGl SOTs from different A. thaliana ecotypes differ in their kinetic properties. However, determinants of substrate specificity and the exact reaction mechanism still need to be clarified. Probably, the three-dimensional structures of more plant proteins need to be solved to analyze the mode of action and the responsible amino acids for substrate binding. In addition to A. thaliana, more plant species from several families need to be investigated to fully elucidate the diversity of sulfated molecules and the way of biosynthesis catalyzed by SOT enzymes.

No MeSH data available.


Related in: MedlinePlus