Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae

cDNA coding for two digestive lysozymes (MdL1 and MdL2) of the Musca domestica housefly was cloned and sequenced. MdL2 is a novel minor lysozyme, whereas MdL1 is the major lysozyme thus far purified from M. domestica midgut. MdL1 and MdL2 were expressed as recombinant proteins in Pichia pastoris, pu...

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Main Authors: F.C. Cançado, P Chimoy Effio, W.R. Terra, S.R. Marana
Format: Article
Language:English
Published: Associação Brasileira de Divulgação Científica 2008-11-01
Series:Brazilian Journal of Medical and Biological Research
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008001100005
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author F.C. Cançado
P Chimoy Effio
W.R. Terra
S.R. Marana
author_facet F.C. Cançado
P Chimoy Effio
W.R. Terra
S.R. Marana
author_sort F.C. Cançado
collection DOAJ
description cDNA coding for two digestive lysozymes (MdL1 and MdL2) of the Musca domestica housefly was cloned and sequenced. MdL2 is a novel minor lysozyme, whereas MdL1 is the major lysozyme thus far purified from M. domestica midgut. MdL1 and MdL2 were expressed as recombinant proteins in Pichia pastoris, purified and characterized. The lytic activities of MdL1 and MdL2 upon Micrococcus lysodeikticus have an acidic pH optimum (4.8) at low ionic strength (μ = 0.02), which shifts towards an even more acidic value, pH 3.8, at a high ionic strength (μ = 0.2). However, the pH optimum of their activities upon 4-methylumbelliferyl N-acetylchitotrioside (4.9) is not affected by ionic strength. These results suggest that the acidic pH optimum is an intrinsic property of MdL1 and MdL2, whereas pH optimum shifts are an effect of the ionic strength on the negatively charged bacterial wall. MdL2 affinity for bacterial cell wall is lower than that of MdL1. Differences in isoelectric point (pI) indicate that MdL2 (pI = 6.7) is less positively charged than MdL1 (pI = 7.7) at their pH optima, which suggests that electrostatic interactions might be involved in substrate binding. In agreement with that finding, MdL1 and MdL2 affinities for bacterial cell wall decrease as ionic strength increases.
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spelling doaj.art-741ca876a109449dbf118871c16e6d022022-12-21T18:47:07ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2008-11-014111969977Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvaeF.C. CançadoP Chimoy EffioW.R. TerraS.R. MaranacDNA coding for two digestive lysozymes (MdL1 and MdL2) of the Musca domestica housefly was cloned and sequenced. MdL2 is a novel minor lysozyme, whereas MdL1 is the major lysozyme thus far purified from M. domestica midgut. MdL1 and MdL2 were expressed as recombinant proteins in Pichia pastoris, purified and characterized. The lytic activities of MdL1 and MdL2 upon Micrococcus lysodeikticus have an acidic pH optimum (4.8) at low ionic strength (μ = 0.02), which shifts towards an even more acidic value, pH 3.8, at a high ionic strength (μ = 0.2). However, the pH optimum of their activities upon 4-methylumbelliferyl N-acetylchitotrioside (4.9) is not affected by ionic strength. These results suggest that the acidic pH optimum is an intrinsic property of MdL1 and MdL2, whereas pH optimum shifts are an effect of the ionic strength on the negatively charged bacterial wall. MdL2 affinity for bacterial cell wall is lower than that of MdL1. Differences in isoelectric point (pI) indicate that MdL2 (pI = 6.7) is less positively charged than MdL1 (pI = 7.7) at their pH optima, which suggests that electrostatic interactions might be involved in substrate binding. In agreement with that finding, MdL1 and MdL2 affinities for bacterial cell wall decrease as ionic strength increases.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008001100005LysozymeDigestive lysozymeSubstrate affinitypH optimum
spellingShingle F.C. Cançado
P Chimoy Effio
W.R. Terra
S.R. Marana
Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae
Brazilian Journal of Medical and Biological Research
Lysozyme
Digestive lysozyme
Substrate affinity
pH optimum
title Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae
title_full Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae
title_fullStr Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae
title_full_unstemmed Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae
title_short Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae
title_sort cloning purification and comparative characterization of two digestive lysozymes from musca domestica larvae
topic Lysozyme
Digestive lysozyme
Substrate affinity
pH optimum
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008001100005
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