1nkf: Difference between revisions
New page: left|200px<br /> <applet load="1nkf" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nkf" /> '''CALCIUM-BINDING PEPTIDE, NMR, 30 STRUCTURES... |
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[[Image:1nkf.gif|left|200px]]<br /> | [[Image:1nkf.gif|left|200px]]<br /><applet load="1nkf" size="350" color="white" frame="true" align="right" spinBox="true" | ||
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'''CALCIUM-BINDING PEPTIDE, NMR, 30 STRUCTURES'''<br /> | '''CALCIUM-BINDING PEPTIDE, NMR, 30 STRUCTURES'''<br /> | ||
==Overview== | ==Overview== | ||
A 12-residue peptide AcDKDGDGYISAAENH2 analogous to the third | A 12-residue peptide AcDKDGDGYISAAENH2 analogous to the third calcium-binding loop of calmodulin strongly coordinates lanthanide ions (K = 10(5) M-1). When metal saturated, the peptide adopts a very rigid structure, the same as in the native protein, with three last residues AAE fixed in the alpha-helical conformation. Therefore, the peptide provides an ideal helix nucleation site for peptide segments attached to its C terminus. NMR and CD investigations of peptide AcDKDGDGYISAAEAAAQNH2 presented in this paper show that residues A13-Q16 form an alpha-helix of very high stability when the La3+ ion is bound to the D1-E12 loop. In fact, the lowest estimates of the helix content in this segment give values of at least 80% at 1 degreesC and 70% at 25 degreesC. This finding is not compatible with existing helix-coil transition theories and helix propagation parameters, s, reported in the literature. We conclude, therefore, that the initial steps of helix propagation are characterized by much larger s values, whereas helix nucleation is even more unfavorable than is believed. In light of our findings, thermodynamics of the nascent alpha-helices is discussed. The problem of CD spectra of very short alpha-helices is also addressed. | ||
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
1NKF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with ACE, NH2 and LA as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1NKF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=ACE:'>ACE</scene>, <scene name='pdbligand=NH2:'>NH2</scene> and <scene name='pdbligand=LA:'>LA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NKF OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: nmr structure]] | [[Category: nmr structure]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:07:02 2008'' | ||
Revision as of 15:07, 21 February 2008
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CALCIUM-BINDING PEPTIDE, NMR, 30 STRUCTURES
OverviewOverview
A 12-residue peptide AcDKDGDGYISAAENH2 analogous to the third calcium-binding loop of calmodulin strongly coordinates lanthanide ions (K = 10(5) M-1). When metal saturated, the peptide adopts a very rigid structure, the same as in the native protein, with three last residues AAE fixed in the alpha-helical conformation. Therefore, the peptide provides an ideal helix nucleation site for peptide segments attached to its C terminus. NMR and CD investigations of peptide AcDKDGDGYISAAEAAAQNH2 presented in this paper show that residues A13-Q16 form an alpha-helix of very high stability when the La3+ ion is bound to the D1-E12 loop. In fact, the lowest estimates of the helix content in this segment give values of at least 80% at 1 degreesC and 70% at 25 degreesC. This finding is not compatible with existing helix-coil transition theories and helix propagation parameters, s, reported in the literature. We conclude, therefore, that the initial steps of helix propagation are characterized by much larger s values, whereas helix nucleation is even more unfavorable than is believed. In light of our findings, thermodynamics of the nascent alpha-helices is discussed. The problem of CD spectra of very short alpha-helices is also addressed.
DiseaseDisease
Known diseases associated with this structure: Cavernous malformations of CNS and retina OMIM:[604214], Cerebral cavernous malformations-1 OMIM:[604214], Hyperkeratotic cutaneous capillary-venous malformations associated with cerebral capillary malformations OMIM:[604214], Leukemia, acute T-cell lymphoblastic OMIM:[603025], Leukemia, acute myeloid OMIM:[603025]
About this StructureAbout this Structure
1NKF is a Single protein structure of sequence from Homo sapiens with , and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Alpha-helix nucleation by a calcium-binding peptide loop., Siedlecka M, Goch G, Ejchart A, Sticht H, Bierzyski A, Proc Natl Acad Sci U S A. 1999 Feb 2;96(3):903-8. PMID:9927666
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