Journal:Acta Cryst F:S2053230X19002693
From Proteopedia
(Difference between revisions)
| (14 intermediate revisions not shown.) | |||
| Line 1: | Line 1: | ||
<StructureSection load='' size='450' side='right' scene='80/809165/Cv/1' caption=''> | <StructureSection load='' size='450' side='right' scene='80/809165/Cv/1' caption=''> | ||
| - | ===Crystal structure of phosphoribulokinase from Synechococcus sp. strain PCC 6301=== | + | ===Crystal structure of phosphoribulokinase from ''Synechococcus sp.'' strain PCC 6301=== |
| - | <big> | + | <big>Robert Wilson, Manajit Hayer-Hartl and Andreas Bracher</big> <ref>doi 10.1107/S2053230X19002693</ref> |
<hr/> | <hr/> | ||
<b>Molecular Tour</b><br> | <b>Molecular Tour</b><br> | ||
| - | Phosphoribulokinase (PRK) catalyses the ATP-dependent phosphorylation of ribulose-5-phosphate to ribulose-1,5-bisphosphate. The enzyme accompanies Rubisco in autotrophic organisms and both are unique to the Calvin-Benson-Bassham (CBB) cycle of photosynthesis. Isoforms of PRK can be grouped in three classes, which occur in proteobacteria, archaea and photosynthetic organisms respectively. The crystal structure of PRK from the cyanobacterium ''Synechococcus sp.'' PCC 6301 presents a structural model for PRK from photosynthetic organisms, such as β-cyanobacteria, most green and red eukaryotic algae, and plants | + | Phosphoribulokinase (PRK) catalyses the ATP-dependent phosphorylation of ribulose-5-phosphate to ribulose-1,5-bisphosphate. The enzyme accompanies Rubisco in autotrophic organisms and both are unique to the Calvin-Benson-Bassham (CBB) cycle of photosynthesis. Isoforms of PRK can be grouped in three classes, which occur in proteobacteria, archaea and photosynthetic organisms respectively. The crystal structure of PRK from the cyanobacterium ''Synechococcus sp.'' PCC 6301 presents a structural model for PRK from photosynthetic organisms, such as β-cyanobacteria, most green and red eukaryotic algae, and plants. The enzyme is dimeric and has an alpha/beta-fold with an 18-stranded beta-sheet at its core. |
Regulation of PRK enzyme activity in response to light controls carbon fixation during photosynthesis. This occurs via reversible formation of disulfide bonds during dark inactivation and complex formation with the adaptor protein CP12 and glyceraldehyde-3-phosphate dehydrogenase, another CBB cycle enzyme. Interestingly, we find a disulphide bond between Cys40 and the P-loop residue Cys18 in our crystal structure, revealing the structural basis for redox-inactivation of PRK activity. A second disulphide bond appears to rigidify the dimer interface and may thereby contribute to regulation by the adaptor protein CP12 and glyceraldehyde-3-phosphate dehydrogenase into a supramolecular complex within which both enzymes are inhibited. | Regulation of PRK enzyme activity in response to light controls carbon fixation during photosynthesis. This occurs via reversible formation of disulfide bonds during dark inactivation and complex formation with the adaptor protein CP12 and glyceraldehyde-3-phosphate dehydrogenase, another CBB cycle enzyme. Interestingly, we find a disulphide bond between Cys40 and the P-loop residue Cys18 in our crystal structure, revealing the structural basis for redox-inactivation of PRK activity. A second disulphide bond appears to rigidify the dimer interface and may thereby contribute to regulation by the adaptor protein CP12 and glyceraldehyde-3-phosphate dehydrogenase into a supramolecular complex within which both enzymes are inhibited. | ||
| + | |||
| + | Perpendicular views of the asymmetric unit in the Syn6301-PRK crystal lattice: | ||
| + | *<scene name='80/809165/Cv/4'>First view</scene>. | ||
| + | *<scene name='80/809165/Cv/5'>Second view</scene>. | ||
| + | The PRK chains A and B are shown as green and yellow ribbons, respectively. The disulphide bonds are represented as yellow sticks. N- and C-termini are indicated. | ||
| + | |||
| + | Comparison of the active sites in ''Syn''6301-PRK, ''Mh''PRK and uridine kinase: | ||
| + | |||
| + | <scene name='80/809165/Cv/7'>Ribbon representation of Syn6301-PRK in the redox-blocked state</scene> (PDB entry [[6hzk]]). The Cys18-Cys40 disulphide bond is represented by yellow stick. Secondary structure elements are indicated. The red pointer indicates the Walker A motif (P-loop). | ||
| + | |||
| + | <scene name='80/809165/Cv/8'>Ribbon representation of MhPRK</scene> (PDB entry [[5b3f]]) in the apo state. The similar view as in the previous scene. The red pointer indicates the Walker A motif (P-loop). | ||
| + | |||
| + | <scene name='80/809165/Cv/11'>Ribbon representation of uridine kinase from Thermus thermophilus</scene> (PDB entry [[3w8r]]) in the substrate-bound state. The substrates cytidine (Ctn) and AMP-PCP (ATP) are presented as cyan and magenta sticks, respectively. The helical hairpin acting as a lid above the substrate binding sites is indicated. | ||
| + | |||
| + | '''PDB references:''' redox-inhibited phosphoribulokinase from ''Synechococcus sp.'' strain PCC 6301, [[6hzk]]; osmate derivative, [[6hzl]]. | ||
<b>References</b><br> | <b>References</b><br> | ||
Current revision
| |||||||||||
This page complements a publication in scientific journals and is one of the Proteopedia's Interactive 3D Complement pages. For aditional details please see I3DC.
