Solution structure and activity of mouse lysozyme M

Obita, Takayuki; Ueda, Tadashi; Imoto, Taiji

doi:10.1007/s000180300012

Cited by 18 publications

(15 citation statements)

References 23 publications

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“…A BLAST analysis of HEL and two mouse lysozymes, type P intestinal [54] and type M milk [55], identifies 49 non-self residues on HEL (they are indicated with the superscript NS ), 30 of them are visible on the molecular surface and would therefore be antibody-accessible. This rather large number of exposed non-self residues is consistent with the experimental evidence for multiple epitopes on HEL antigen [56][57][58][59].…”

Section: Topography Of Functional Epitopes On Protein Antigensmentioning

confidence: 99%

A Structurally Based Approach to Determine HLA Compatibility at the Humoral Immune Level

2006

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HLAMatchmaker is a structurally based matching program. Each HLA antigen is viewed as a string of epitopes represented by short sequences (triplets) involving polymorphic amino acid residues in antibody-accessible positions. HLAMatchmaker determines which triplets are different between donor and recipient and this algorithm is clinically useful in determining HLA mismatch acceptability. Triplets provide however an incomplete description of the HLA epitope repertoire and expanded criteria must be used including longer sequences and polymorphic residues in discontinuous positions. Such criteria should consider the structural basis of antibody-antigen interactions including contact areas and binding energy, the essence of antigenicity.This report describes the development of a structurally defined HLA epitope repertoire based on stereochemical modeling of crystallized complexes of antibodies and different protein antigens. This analysis considered also data in the literature about contributions of amino acid residues to antigenantibody binding energy. The results have led to the concept that HLA antigens like other antigenic proteins have structural epitopes consisting of 15-22 residues that constitute the binding face with alloantibody. Each structural epitope has a functional epitope of about 2-5 residues that dominate the strength and specificity of binding with antibody. The remaining residues of a structural epitope provide supplementary interactions that increase the stability of the antigen-antibody complex. Each functional epitope has one or more non-self residues and the term "eplet" is used to describe polymorphic HLA residues within 3.0-3.5 Ångstroms of a given sequence position on the molecular surface. Many eplets represent short linear sequences identical to those referred to as triplets but others have residues in discontinuous sequence positions that cluster together on the molecular surface. Serologically defined HLA determinants correspond well to eplets. The eplet version of HLAMatchmaker represents therefore a more complete repertoire of structurally defined HLA epitopes and provides a more detailed assessment of HLA compatibility.

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Section: Topography Of Functional Epitopes On Protein Antigensmentioning

confidence: 99%

A Structurally Based Approach to Determine HLA Compatibility at the Humoral Immune Level

2006

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“…The three-dimensional structure of lysozyme M, determined by nuclear magnetic resonance spectroscopy, identified E35 and D53 as active site residues in the mouse enzyme (19). Substitution of serine for aspartic acid in the active site of hen egg white lysozyme completely ablated muramidase activity (20).…”

mentioning

confidence: 99%

The Peptidoglycan-Degrading Property of Lysozyme Is Not Required for Bactericidal Activity In Vivo

Nash

Ballard

Weaver

et al. 2006

The Journal of Immunology

137

113

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Lysozyme is an abundant, cationic antimicrobial protein that plays an important role in pulmonary host defense. Increased concentration of lysozyme in the airspaces of transgenic mice enhanced bacterial killing whereas lysozyme deficiency resulted in increased bacterial burden and morbidity. Lysozyme degrades peptidoglycan in the bacterial cell wall leading to rapid killing of Gram-positive organisms; however, this mechanism cannot account for the protective effect of lysozyme against Gram-negative bacteria. The current study was therefore designed to test the hypothesis that the catalytic activity (muramidase activity) of lysozyme is not required for bacterial killing in vivo. Substitution of serine for aspartic acid at position 53 (D53S) in mouse lysozyme M completely ablated muramidase activity. Muramidase-deficient recombinant lysozyme (LysMD53S) killed both Gram-positive and Gram-negative bacteria in vitro. Targeted expression of LysMD53S in the respiratory epithelium of wild-type (LysM+/+/LysMD53S) or lysozyme Mnull mice (LysM−/−/LysMD53S) resulted in significantly elevated lysozyme protein in the airspaces without any increase in muramidase activity. Intratracheal challenge of transgenic mice with Gram-positive or Gram-negative bacteria resulted in a significant increase in bacterial burden in LysM−/− mice that was completely reversed by targeted expression of LysMD53S. These results indicate that the muramidase activity of lysozyme is not required for bacterial killing in vitro or in vivo.

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“…In fact, Asn127 could interact with Tyr124 through the hydrogen bond network in the vicinity of Cys128-Cys6, and racemization of hydroxyproline in Homo tirolensis relates to Tyr oxidation and hydroxyl radical generation [44]. Additionally, from the solution structure of ML using NMR [19] and molecular dynamics simulation (data not shown here), Asn127 was suggested to locate at an exposed position of loose structure in which it contacts with bulk water. Thus, the loose structure allows the specific racemization at Asn127.…”

Section: Discussionmentioning

confidence: 87%

“…The reactive C-terminal (Val130) carboxylate in ML is one of the candidates for involvement in the racemization at Asn127. However, the solution structure of ML using NMR [19] and molecular dynamic simulation (data not shown), suggested that the C-terminal carboxylate is unlikely to access Asn127. Recently, Li et al [35] examined the conversion from L-Asn to D-Asn using the peptide containing Asn, and found that this conversion in the peptide partially occurred without deamidation, indicating that succinimide formation at the Asn residue did not occur.…”

Section: Discussionmentioning

confidence: 87%

“…Notable examples of spontaneous modification are pyroglutamylation of Glu/Gln residues, deamidation of Asn/Gln residues, isomerization of Asp/Asn residues cleavage of the peptide bond in Asp/Asn-Pro sequences [6] and racemization of other amino acids. three-dimensional structure has already been analyzed using nuclear magnetic resonance (NMR) spectroscopy [19]. Therefore, it is a suitable model to study protein deterioration under physiological conditions.…”

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confidence: 99%

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Evidence for a novel racemization process of an asparaginyl residue in mouse lysozyme under physiological conditions

Ueno

Ueda

Sakai

et al. 2005

CMLS, Cell. Mol. Life Sci.

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We examined chemical reactions in mouse lysozyme after incubation under physiological conditions (pH 7 and 37 degrees C). After incubation for 8 weeks, racemization was observed specifically at Asn127 among the 19 Asp/Asn residues in mouse lysozyme. Furthermore, analysis of the primary structure showed that the racemized residue was not Asp, but Asn, which demonstrates that deamidation and isomerization did not occur. These results mean that this racemization occurs without forming a succinimide intermediate. This is the first example of D-asparaginyl formation in a protein occurring during the racemization process under physiological conditions.

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Solution structure and activity of mouse lysozyme M

Cited by 18 publications

References 23 publications

A Structurally Based Approach to Determine HLA Compatibility at the Humoral Immune Level

A Structurally Based Approach to Determine HLA Compatibility at the Humoral Immune Level

The Peptidoglycan-Degrading Property of Lysozyme Is Not Required for Bactericidal Activity In Vivo

Evidence for a novel racemization process of an asparaginyl residue in mouse lysozyme under physiological conditions

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