3lf0 | pdb_00003lf0

Crystal structure of the ATP bound Mycobacterium tuberculosis nitrogen regulatory PII protein

spinqualitylabelsall models 3lf0, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3lf0 is a 3 chain structure with sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ATP Related: 3bzq Gene: glnB, MT2987, MTCY338.08c, Rv2919c (Mycobacterium tuberculosis) Resources: FirstGlance, OCA, RCSB, PDBsum Function [GLNB_MYCTU] In nitrogen-limiting conditions, when the ratio of Gln to 2-ketoglutarate decreases, P-II is uridylylated to P-II-UMP. P-II-UMP allows the deadenylation of glutamine synthetase (GS), thus activating the enzyme. Conversely, in nitrogen excess P-II is deuridylated and promotes the adenylation of GS. P-II indirectly controls the transcription of the GS gene (glnA). P-II prevents NR-II-catalyzed conversion of NR-I to NR-I-phosphate, the transcriptional activator of glnA. When P-II is uridylylated to P-II-UMP, these events are reversed (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed PII constitutes a family of signal transduction proteins that act as nitrogen sensors in microorganisms and plants. Mycobacterium tuberculosis (Mtb) has a single homologue of PII whose precise role has as yet not been explored. We have solved the crystal structures of the Mtb PII protein in its apo and ATP bound forms to 1.4 and 2.4 A resolutions, respectively. The protein forms a trimeric assembly in the crystal lattice and folds similarly to the other PII family proteins. The Mtb PII:ATP binary complex structure reveals three ATP molecules per trimer, each bound between the base of the T-loop of one subunit and the C-loop of the neighboring subunit. In contrast to the apo structure, at least one subunit of the binary complex structure contains a completely ordered T-loop indicating that ATP binding plays a role in orienting this loop region towards target proteins like the ammonium transporter, AmtB. Arg38 of the T-loop makes direct contact with the gamma-phosphate of the ATP molecule replacing the Mg(2+) position seen in the Methanococcus jannaschii GlnK1 structure. The C-loop of a neighboring subunit encloses the other side of the ATP molecule, placing the GlnK specific C-terminal 3(10) helix in the vicinity. Homology modeling studies with the E. coli GlnK:AmtB complex reveal that Mtb PII could form a complex similar to the complex in E. coli. The structural conservation and operon organization suggests that the Mtb PII gene encodes for a GlnK protein and might play a key role in the nitrogen regulatory pathway. Crystal structures of the apo and ATP bound Mycobacterium tuberculosis nitrogen regulatory PII protein.,Shetty ND, Reddy MC, Palaninathan SK, Owen JL, Sacchettini JC Protein Sci. 2010 Aug;19(8):1513-24. PMID:20521335 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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