Crystal structure of a fungal protease inhibitor from Antheraea mylitta.
J Struct Biol
; 166(1): 79-87, 2009 Apr.
Article
em En
| MEDLINE
| ID: mdl-19263521
ABSTRACT
Indian tasar silk is produced by a wild insect called Antheraea mylitta. Insects do not have any antigen-antibody mediated immune system like vertebrates but they produce a wide variety of effector proteins and peptides possessing potent antifungal and antibacterial activity to combat microbial attack. Antheraea mylitta expresses a fungal protease inhibitor AmFPI-1, in the hemolymph that inhibits alkaline protease of Aspergillus oryzae for protection against fungal infection. AmFPI-1 is purified from the hemolymph, crystallized and the structure is solved using the single isomorphous replacement with anomalous scattering (SIRAS) method to a resolution of 2.1 A. AmFPI-1 is a single domain protein possessing a unique fold that consists of three helices and five beta strands stabilized by a network of six disulfide bonds. The reactive site of AmFPI-1 is located in the loop formed by residues 46-66, wherein Lys54 is the P(1) residue. Superimposition of the loop with reactive sites of other canonical protease inhibitors shows that reactive site conformation of AmFPI-1 is similar to them. The structure of AmFPI-1 provides a framework for the docking of a 11 complex between AmFPI-1 and alkaline protease. This study addresses the structural basis of AmFPI-1's specificity towards a fungal serine protease but not to mammalian trypsin and may help in designing specific inhibitors against fungal proteases.
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Base de dados:
MEDLINE
Assunto principal:
Inibidores de Proteases
/
Proteínas de Insetos
/
Mariposas
/
Antifúngicos
Limite:
Animals
Idioma:
En
Revista:
J Struct Biol
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Índia