1wkm
From Proteopedia
(New page: 200px<br /><applet load="1wkm" size="450" color="white" frame="true" align="right" spinBox="true" caption="1wkm, resolution 2.30Å" /> '''THE PRODUCT BOUND FO...) |
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caption="1wkm, resolution 2.30Å" /> | caption="1wkm, resolution 2.30Å" /> | ||
'''THE PRODUCT BOUND FORM OF THE MN(II)LOADED METHIONINE AMINOPEPTIDASE FROM HYPERTHERMOPHILE PYROCOCCUS FURIOSUS'''<br /> | '''THE PRODUCT BOUND FORM OF THE MN(II)LOADED METHIONINE AMINOPEPTIDASE FROM HYPERTHERMOPHILE PYROCOCCUS FURIOSUS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Methionine aminopeptidases (MetAPs) are ubiquitous metallohydrolases that | + | Methionine aminopeptidases (MetAPs) are ubiquitous metallohydrolases that remove the N-terminal methionine from nascent polypeptide chains. Although various crystal structures of MetAP in the presence of inhibitors have been solved, the structural aspects of the product-bound step has received little attention. Both perpendicular- and parallel-mode electron paramagnetic resonance (EPR) spectra were recorded for the Mn(II)-loaded forms of the type-I (Escherichia coli) and type-II (Pyrococcus furiosus) MetAPs in the presence of the reaction product l-methionine (L-Met). In general, similar EPR features were observed for both [MnMn(EcMetAP-I)]-L-Met and [MnMn(PfMetAP-II)]-L-Met. The observed perpendicular-mode EPR spectra consisted of a six-line hyperfine pattern at g = 2.03 (A = 8.8 mT) with less intense signals with eleven-line splitting at g = 2.4 and 1.7 (A = 4.4 mT). The former feature results from mononuclear, magnetically isolated Mn(II) ions and this signal are 3-fold more intense in the [MnMn(PfMetAP-II)]-L-Met EPR spectrum than in the [MnMn(EcMetAP-I)]-L-Met spectrum. Inspection of the EPR spectra of both [MnMn(EcMetAP-I)]-L-Met and [MnMn(PfMetAP-II)]-L-Met at 40 K in the parallel mode reveals that the [Mn(EcMetAP-I)]-L-Met spectrum exhibits a well-resolved hyperfine split pattern at g = 7.6 with a hyperfine splitting constant of A = 4.4 mT. These data suggest the presence of a magnetically coupled dinuclear Mn(II) center. On the other hand, a similar feature was not observed for the [MnMn(PfMetAP-II)]-L-Met complex. Therefore, the EPR data suggest that L-Met binds to [MnMn(EcMetAP-I)] differently than [MnMn(PfMetAP-II)]. To confirm these data, the X-ray crystal structure of [MnMn(PfMetAP-II)]-L-Met was solved to 2.3 A resolution. Both Mn1 and Mn2 reside in a distorted trigonal bipyramidal geometry, but the bridging water molecule, observed in the [CoCo(PfMetAP-II)] structure, is absent. Therefore, L-Met binding displaces this water molecule, but the carboxylate oxygen atom of L-Met does not bridge between the two Mn(II) ions. Instead, a single carboxylate oxygen atom of L-Met interacts with only Mn1, while the N-terminal amine nitrogen atom binds to M2. This L-Met binding mode is different from that observed for L-Met binding [CoCo(EcMetAP-I)]. Therefore, the catalytic mechanisms of type-I MetAPs may differ somewhat from type-II enzymes when a dinuclear metalloactive site is present. |
==About this Structure== | ==About this Structure== | ||
| - | 1WKM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pyrococcus_furiosus Pyrococcus furiosus] with MN and MET as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Methionyl_aminopeptidase Methionyl aminopeptidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.11.18 3.4.11.18] Full crystallographic information is available from [http:// | + | 1WKM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pyrococcus_furiosus Pyrococcus furiosus] with <scene name='pdbligand=MN:'>MN</scene> and <scene name='pdbligand=MET:'>MET</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Methionyl_aminopeptidase Methionyl aminopeptidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.11.18 3.4.11.18] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WKM OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Bennett, B.]] | [[Category: Bennett, B.]] | ||
| - | [[Category: Copik, A | + | [[Category: Copik, A J.]] |
| - | [[Category: Holz, R | + | [[Category: Holz, R C.]] |
| - | [[Category: Jang, S | + | [[Category: Jang, S B.]] |
[[Category: Meng, L.]] | [[Category: Meng, L.]] | ||
| - | [[Category: Nocek, B | + | [[Category: Nocek, B P.]] |
| - | [[Category: Peters, J | + | [[Category: Peters, J W.]] |
[[Category: Ruebush, S.]] | [[Category: Ruebush, S.]] | ||
| - | [[Category: Swierczek, S | + | [[Category: Swierczek, S I.]] |
| - | [[Category: souza, V | + | [[Category: souza, V M.D.]] |
[[Category: MET]] | [[Category: MET]] | ||
[[Category: MN]] | [[Category: MN]] | ||
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[[Category: methionine complex]] | [[Category: methionine complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:45:23 2008'' |
Revision as of 13:45, 21 February 2008
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THE PRODUCT BOUND FORM OF THE MN(II)LOADED METHIONINE AMINOPEPTIDASE FROM HYPERTHERMOPHILE PYROCOCCUS FURIOSUS
Overview
Methionine aminopeptidases (MetAPs) are ubiquitous metallohydrolases that remove the N-terminal methionine from nascent polypeptide chains. Although various crystal structures of MetAP in the presence of inhibitors have been solved, the structural aspects of the product-bound step has received little attention. Both perpendicular- and parallel-mode electron paramagnetic resonance (EPR) spectra were recorded for the Mn(II)-loaded forms of the type-I (Escherichia coli) and type-II (Pyrococcus furiosus) MetAPs in the presence of the reaction product l-methionine (L-Met). In general, similar EPR features were observed for both [MnMn(EcMetAP-I)]-L-Met and [MnMn(PfMetAP-II)]-L-Met. The observed perpendicular-mode EPR spectra consisted of a six-line hyperfine pattern at g = 2.03 (A = 8.8 mT) with less intense signals with eleven-line splitting at g = 2.4 and 1.7 (A = 4.4 mT). The former feature results from mononuclear, magnetically isolated Mn(II) ions and this signal are 3-fold more intense in the [MnMn(PfMetAP-II)]-L-Met EPR spectrum than in the [MnMn(EcMetAP-I)]-L-Met spectrum. Inspection of the EPR spectra of both [MnMn(EcMetAP-I)]-L-Met and [MnMn(PfMetAP-II)]-L-Met at 40 K in the parallel mode reveals that the [Mn(EcMetAP-I)]-L-Met spectrum exhibits a well-resolved hyperfine split pattern at g = 7.6 with a hyperfine splitting constant of A = 4.4 mT. These data suggest the presence of a magnetically coupled dinuclear Mn(II) center. On the other hand, a similar feature was not observed for the [MnMn(PfMetAP-II)]-L-Met complex. Therefore, the EPR data suggest that L-Met binds to [MnMn(EcMetAP-I)] differently than [MnMn(PfMetAP-II)]. To confirm these data, the X-ray crystal structure of [MnMn(PfMetAP-II)]-L-Met was solved to 2.3 A resolution. Both Mn1 and Mn2 reside in a distorted trigonal bipyramidal geometry, but the bridging water molecule, observed in the [CoCo(PfMetAP-II)] structure, is absent. Therefore, L-Met binding displaces this water molecule, but the carboxylate oxygen atom of L-Met does not bridge between the two Mn(II) ions. Instead, a single carboxylate oxygen atom of L-Met interacts with only Mn1, while the N-terminal amine nitrogen atom binds to M2. This L-Met binding mode is different from that observed for L-Met binding [CoCo(EcMetAP-I)]. Therefore, the catalytic mechanisms of type-I MetAPs may differ somewhat from type-II enzymes when a dinuclear metalloactive site is present.
About this Structure
1WKM is a Single protein structure of sequence from Pyrococcus furiosus with and as ligands. Active as Methionyl aminopeptidase, with EC number 3.4.11.18 Full crystallographic information is available from OCA.
Reference
EPR and X-ray crystallographic characterization of the product-bound form of the MnII-loaded methionyl aminopeptidase from Pyrococcus furiosus., Copik AJ, Nocek BP, Swierczek SI, Ruebush S, Jang SB, Meng L, D'souza VM, Peters JW, Bennett B, Holz RC, Biochemistry. 2005 Jan 11;44(1):121-9. PMID:15628852
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