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Protein strain in b...
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De Kerpel, Jan O ACatholic University of Leuven
(författare)
Protein strain in blue copper proteins studied by free energy perturbations
- Artikel/kapitelEngelska1999
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Nummerbeteckningar
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LIBRIS-ID:oai:lup.lub.lu.se:3070384e-0534-4580-aa7f-0da5c79f6594
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https://lup.lub.lu.se/record/3070384e-0534-4580-aa7f-0da5c79f6594URI
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https://doi.org/10.1002/(SICI)1097-0134(19990801)36:2<157::AID-PROT3>3.0.CO;2-YDOI
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Språk:engelska
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Sammanfattning på:engelska
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Ämneskategori:art swepub-publicationtype
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Ämneskategori:ref swepub-contenttype
Anmärkningar
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Free energy perturbations have been performed on two blue copper proteins, plastocyanin and nitrite reductase. By changing the copper coordination geometry, force constants, and charges, we have estimated the maximum energy with which the proteins may distort the copper coordination sphere. By comparing this energy with the quantum chemical energy cost for the same perturbation on the isolated copper complex, various hypotheses about protein strain have been tested. The calculations show that the protein can only modify the copper-methionine bond length by a modest amount of energy -- <5 kJ/mol--and they lend no support to the suggestion that the quite appreciable difference in the copper coordination geometry encountered in the two proteins is a result of the proteins enforcing different Cu- methionine bond lengths. On the contrary, this bond is very flexible, and neither the geometry nor the electronic structure change appreciably when the bond length is changed. Moreover, the proteins are rather indifferent to the length of this bond. Instead, the Cu(II) coordination geometries in the two proteins represent two distinct minima on the potential surface of the copper ligand sphere, characterized by different electronic structures, a tetragonal, mainly or-bonded, structure in nitrite reductase and a trigonal, π-bonded, structure in plastocyanin. In vacuum, the structures have almost the same energy, and they are stabilized in the proteins by a combination of geometric and electrostatic interactions. Plastocyanin favors the bond lengths and electrostatics of the trigonal structure, whereas in nitrite reductase, the angles are the main discriminating factor.
Ämnesord och genrebeteckningar
Biuppslag (personer, institutioner, konferenser, titlar ...)
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Ryde, UlfLund University,Lunds universitet,Beräkningskemi,Enheten för fysikalisk och teoretisk kemi,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Computational Chemistry,Physical and theoretical chemistry,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)teok-ury
(författare)
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Catholic University of LeuvenBeräkningskemi
(creator_code:org_t)
Sammanhörande titlar
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Ingår i:Proteins: Structure, Function and Genetics36:2, s. 157-1740887-3585
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