Structural analysis of free and enzyme-bound amaranth alpha-amylase inhibitor: classification within the knottin fold superfamily and analysis of its functional flexibility.
Protein Eng
; 14(9): 639-46, 2001 Sep.
Article
em En
| MEDLINE
| ID: mdl-11707609
ABSTRACT
The three-dimensional structure of the amaranth alpha-amylase inhibitor (AAI) adopts a knottin fold of abcabc topology. Upon binding to alpha-amylase, it adopts a more compact conformation characterized by an increased number of intramolecular hydrogen bonds, a decreased volume and in addition a trans to cis isomerization of Pro20. A systematic analysis of the 3-D structural databanks revealed that similar proteins and domains share with AAI the characteristic presence of proline residues, many of which are in a cis backbone conformation. As these proteins fulfil a variety of functional roles and are expressed in very different organisms, we conclude that the structure of the knottin fold, including the propensity of the cis bond, are the result of convergent evolution.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
/
Amaranthus
/
Cistina
/
Inibidores Enzimáticos
/
Alfa-Amilases
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Protein Eng
Assunto da revista:
BIOQUIMICA
/
BIOTECNOLOGIA
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Itália