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| {{STRUCTURE_2p04| PDB=2p04 | SCENE= }} | | {{STRUCTURE_2p04| PDB=2p04 | SCENE= }} |
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| '''2.1 Ang structure of the dimerized PAS domain of signal transduction histidine kinase from Nostoc punctiforme PCC 73102 with homology to the H-NOXA/H-NOBA domain of the soluble guanylyl cyclase'''
| | ===2.1 Ang structure of the dimerized PAS domain of signal transduction histidine kinase from Nostoc punctiforme PCC 73102 with homology to the H-NOXA/H-NOBA domain of the soluble guanylyl cyclase=== |
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| ==Overview==
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| Signal transduction histidine kinases (STHK) are key for sensing environmental stresses, crucial for cell survival, and attain their sensing ability using small molecule binding domains. The N-terminal domain in an STHK from Nostoc punctiforme is of unknown function yet is homologous to the central region in soluble guanylyl cyclase (sGC), the main receptor for nitric oxide (NO). This domain is termed H-NOXA (or H-NOBA) because it is often associated with the heme-nitric oxide/oxygen binding (H-NOX) domain. A structure-function approach was taken to investigate the role of H-NOXA in STHK and sGC. We report the 2.1 A resolution crystal structure of the dimerized H-NOXA domain of STHK, which reveals a Per-Arnt-Sim (PAS) fold. The H-NOXA monomers dimerize in a parallel arrangement juxtaposing their N-terminal helices and preceding residues. Such PAS dimerization is similar to that previously observed for EcDOS, AvNifL, and RmFixL. Deletion of 7 N-terminal residues affected dimer organization. Alanine scanning mutagenesis in sGC indicates that the H-NOXA domains of sGC could adopt a similar dimer organization. Although most putative interface mutations did decrease sGCbeta1 H-NOXA homodimerization, heterodimerization of full-length heterodimeric sGC was mostly unaffected, likely due to the additional dimerization contacts of sGC in the coiled-coil and catalytic domains. Exceptions are mutations sGCalpha1 F285A and sGCbeta1 F217A, which each caused a drastic drop in NO stimulated activity, and mutations sGCalpha1 Q368A and sGCbeta1 Q309A, which resulted in both a complete lack of activity and heterodimerization. Our structural and mutational results provide new insights into sGC and STHK dimerization and overall architecture.
| | The line below this paragraph, {{ABSTRACT_PUBMED_18006497}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 18006497 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_18006497}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Pas-like fold dimer]] | | [[Category: Pas-like fold dimer]] |
| [[Category: Transferase]] | | [[Category: Transferase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Apr 24 09:26:25 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 00:42:55 2008'' |