Análisis proteómico de la expresión de enzimas que degradan lignocelulosa en el secretoma de Penicillium purpurogenum crecido en distintas fuentes de carbono
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2010
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es
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Universidad Andrés Bello
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Resumen
RESUMEN: Penicilliumpurpurogenum es un hongo capaz de crecer en fuentes de carbono
provenientes de diversas fuentes vegetales, lo que refleja una gran capacidad de
adaptación al medio. Por tratarse de sustratos insolubles y de variada
composición, para degradarlos en forma eficiente el hongo debe adaptar su
secreción de enzimas al medio extracelular (secretoma). En esta tesis se ha
comparado el patrón de secreción proteico al crecer el hongo en fuentes de
carbono complejas como coseta de remolacha, xilanoacetilado y pectina, como
también en fuentes de carbono simples como glucosa y fructosa. Se ha usado un
enfoque proteómico en condiciones desnaturantes y en condiciones no
desnaturantes lo que nos entrega dos perspectivas diferentes. En condiciones
desnaturantes hemos identificado proteínas como pectinasas, β-xilosidasas y
manosidasas diferencialmente expresadas en fuentes de carbono complejas, las
que no están presentes en las fuentes simples. En el enfoque no desnaturante se
detectó en el secretoma de cultivos en las fuentes complejas (pero no en las
simples) la presencia de proteínas de alto peso molecular cataliticamente activas.
Estas estructuras corresponden a complejos multienzimáticos constituidos por
una diversidad de enzimas con las actividades necesarias para degradar
lignocelulosa. Penicillium purpurogenum, por lo tanto, posee mecanismos de
regulación que involucran la expresión diferencial de enzimas, las que a su vez
interactúan entre ellas, lo que es dependiente de la composición química del
sustrato.
ABSTRACT: Penicilliumpurpurogenum is a fungus able to grow on carbon sources from different plant sources thus reflecting a great environmental adaptability. Since those substrates are insoluble and of different composition, in order to degrade them efficiently the fungus must adapt its enzymatic secretion (secretome). In this thesis the secreted protein pattern from cultures of complex carbon sources such as acetylated xylan, sugar beet pulp and pectin, are compared to those from simple sources such as fructose and glucose. A proteomic analysis of the secretome under denaturing and non-denaturing conditions gives two different perspectives. Under denaturingconditions proteins have been identified such as pectinases, β-xylosidases and mannosidases, which are differentially expressed in complex carbon sources. Under non-denaturing conditions high molecular weight catalytically active proteins have been detected when the fungus grows on complexes carbon sources. These structures are multienzyme complexes that harbor a wide diversity of enzymes needed to degrade lignocellulose. Thus, Penicilliumpurpurogenum employs regulatory mechanisms for the differential expression of enzymes and for protein-protein interactions, both dependent of the chemical composition of the carbon source.
ABSTRACT: Penicilliumpurpurogenum is a fungus able to grow on carbon sources from different plant sources thus reflecting a great environmental adaptability. Since those substrates are insoluble and of different composition, in order to degrade them efficiently the fungus must adapt its enzymatic secretion (secretome). In this thesis the secreted protein pattern from cultures of complex carbon sources such as acetylated xylan, sugar beet pulp and pectin, are compared to those from simple sources such as fructose and glucose. A proteomic analysis of the secretome under denaturing and non-denaturing conditions gives two different perspectives. Under denaturingconditions proteins have been identified such as pectinases, β-xylosidases and mannosidases, which are differentially expressed in complex carbon sources. Under non-denaturing conditions high molecular weight catalytically active proteins have been detected when the fungus grows on complexes carbon sources. These structures are multienzyme complexes that harbor a wide diversity of enzymes needed to degrade lignocellulose. Thus, Penicilliumpurpurogenum employs regulatory mechanisms for the differential expression of enzymes and for protein-protein interactions, both dependent of the chemical composition of the carbon source.
Notas
Tesis (Doctor en Biociencias Moleculares)
Palabras clave
Lignocelulosa -- Biodegradación., Penicillium Purpurogenum.