Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Properties of normal and mutant polypeptide fragments from the dimer self-association sites of human red cell spectrin
Autore:
Lecomte, MC; Nicolas, G; Dhermy, D; Pinder, JC; Gratzer, WB;
Indirizzi:
Univ London Kings Coll, Randall Inst, MRC, Muscle & Cell Motil Unit, London Univ London Kings Coll London England WC2B 5RL & Cell Motil Unit, London Fac Med Bichat, INSERM, U409, F-75870 Paris 18, France Fac Med Bichat Paris France 18 t, INSERM, U409, F-75870 Paris 18, France
Titolo Testata:
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS
fascicolo: 3, volume: 28, anno: 1999,
pagine: 208 - 215
SICI:
0175-7571(1999)28:3<208:PONAMP>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
DYSTROPHIN ROD DOMAIN; HELICAL COILED-COILS; FOLDING UNIT; HEREDITARY ELLIPTOCYTOSIS; CONFORMATIONAL UNIT; STABILITY; PROTEIN; MUTATIONS; SECONDARY; PEPTIDES;
Keywords:
spectrin; self-association; erythrocyte; hereditary elliptocytosis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Gratzer, WB UnivDruryon Kings Coll, Randall Inst, MRC, Muscle & Cell MotilUnit, 26-29 Univ London Kings Coll 26-29 Drury lane London England WC2B 5RL
Citazione:
M.C. Lecomte et al., "Properties of normal and mutant polypeptide fragments from the dimer self-association sites of human red cell spectrin", EUR BIOPHYS, 28(3), 1999, pp. 208-215

Abstract

We have examined the properties and interactions of expressed polypeptide fragments from the N-terminus of the alpha-chain and the C-terminus of the beta-chain of human erythroid spectrin. Each polypeptide comprises one complete structural repeating unit, together with the incomplete repeat that interacts with its partner when spectrin tetramers are formed. The shared repeat thus generated is made up of two helices from the C-terminal part of the beta-chain and one helix from the N-terminus of the alpha-chain. Three mutant beta-chain fragments with amino acid substitutions in the incomplete terminal repeat were also studied. The alpha- and beta-chain fragments were both substantially monomeric, as shown by sedimentation equilibrium. Circular dichroism analysis and thermal denaturation profiles revealed that the complete repeat present in each Fragment had entered the stable tertiary fold. Unexpectedly, the conformational stability of the folded beta-chain repeat was found to be grossly perturbed by the mutations, all of them well beyond its C-terminal boundary: possible explanations for this phemomenon are considered. Sedimentation equilibrium showed that in equimolar mixtures thewildtype alpha- and beta-chain peptides formed a 1:1 complex. Mixing curves, observed by circular dichroism, revealed that association was accompanied by an increase in alpha-helicity. From continuous-variation profiles an association constant in the range 1-2x10(6) M-1 was inferred. The association was unaffected by the apparently unstructured anionic tail of 54 residues, found at the C-terminus of the spectrin beta-chain. Of the three mutations in the beta-chain fragment, one (an Ala-->Val replacement in the A helix segment of the incomplete repeat) had a relatively small effect on the association with the alpha-chain fragment, whereas Trp-->Arg mutations in the Aand in the remote B helix segments were much more deleterious. These observations are consistent with the relative severities of the haemolytic conditions associated with the mutations.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/04/20 alle ore 06:40:18