|
|
| Line 1: |
Line 1: |
| [[Image:2fb3.gif|left|200px]] | | {{Seed}} |
| | [[Image:2fb3.png|left|200px]] |
|
| |
|
| <!-- | | <!-- |
| Line 9: |
Line 10: |
| {{STRUCTURE_2fb3| PDB=2fb3 | SCENE= }} | | {{STRUCTURE_2fb3| PDB=2fb3 | SCENE= }} |
|
| |
|
| '''Structure of MoaA in complex with 5'-GTP'''
| | ===Structure of MoaA in complex with 5'-GTP=== |
|
| |
|
|
| |
|
| ==Overview==
| | <!-- |
| The first step in molybdenum cofactor biosynthesis, the conversion of 5'-GTP to precursor Z, an oxygen-sensitive tetrahydropyranopterin is catalyzed by the S-adenosylmethionine (SAM)-dependent enzyme MoaA and the accessory protein MoaC. This reaction involves the radical-initiated intramolecular rearrangement of the guanine C8 atom. MoaA harbors an N-terminal [4Fe-4S] cluster, which is involved in the reductive cleavage of SAM and generates a 5'-deoxyadenosyl radical (5'-dA*), and a C-terminal [4Fe-4S] cluster presumably involved in substrate binding and/or activation. Biochemical studies identified residues involved in 5'-GTP binding and the determinants of nucleotide specificity. The crystal structure of MoaA in complex with 5'-GTP confirms the biochemical data and provides valuable insights into the subsequent radical reaction. MoaA binds 5'-GTP with high affinity and interacts through its C-terminal [4Fe-4S] cluster with the guanine N1 and N2 atoms, in a yet uncharacterized binding mode. The tightly anchored triphosphate moiety prevents the escape of radical intermediates. This structure also visualizes the L-Met and 5'-dA cleavage products of SAM. Rotation of the 5'-dA ribose and/or conformational changes of the guanosine are proposed to bring the 5'-deoxyadenosyl radical into close proximity of either the ribose C2' and C3' or the guanine C8 carbon atoms leading to hydrogen abstraction. | | The line below this paragraph, {{ABSTRACT_PUBMED_16632608}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 16632608 is the PubMed ID number. |
| | --> |
| | {{ABSTRACT_PUBMED_16632608}} |
|
| |
|
| ==About this Structure== | | ==About this Structure== |
| Line 28: |
Line 32: |
| [[Category: S-adenosylmethionine]] | | [[Category: S-adenosylmethionine]] |
| [[Category: Tim barrel]] | | [[Category: Tim barrel]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 03:40:51 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 03:02:36 2008'' |