title: Crystal structure analysis of peroxidase from the palm tree Chamaerops excelsa.
abstract: Palm tree peroxidases are known to be very stable enzymes and the peroxidase from the Chamaerops excelsa (CEP), which has a high pH and thermal stability, is no exception. To date, the structural and molecular events underscoring such biochemical behavior have not been explored in depth. In order to identify the structural characteristics accounting for the high stability of palm tree peroxidases, we solved and refined the X-ray structure of native CEP at a resolution of 2.6 Å. The CEP structure has an overall fold typical of plant peroxidases and confirmed the conservation of characteristic structural elements such as the heme group and calcium ions. At the same time the structure revealed important modifications in the amino acid residues in the vicinity of the exposed heme edge region, involved in substrate binding, that could account for the morphological variations among palm tree peroxidases through the disruption of molecular interactions at the second binding site. These modifications could alleviate the inhibition of enzymatic activity caused by molecular interactions at the latter binding site. Comparing the CEP crystallographic model described here with other publicly available peroxidase structures allowed the identification of a noncovalent homodimer assembly held together by a number of ionic and hydrophobic interactions. We demonstrate, that this dimeric arrangement results in a more stable protein quaternary structure through stabilization of the regions that are highly dynamic in other peroxidases. In addition, we resolved five N-glycosylation sites, which might also contribute to enzyme stability and resistance against proteolytic cleavage.
authors: Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense 400, São Carlos, SP 13560-970, Brazil.
authors: Amanda
authors: A
authors: Bernardes
authors: Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense 400, São Carlos, SP 13560-970, Brazil.
authors: Larissa C
authors: LC
authors: Textor
authors: Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense 400, São Carlos, SP 13560-970, Brazil.
authors: Jademilson C
authors: JC
authors: Santos
authors: Departamento de Química Física, Facultad de Química, Universidad de Salamanca, 37008 Salamanca, Spain.
authors: Nazaret Hidalgo
authors: NH
authors: Cuadrado
authors: Departament of Biochemistry, Microbiology and Biotechnology, Far Eastern Federal University, 690600 Vladivostok, Russia.
authors: Eduard Ya
authors: EY
authors: Kostetsky
authors: Departamento de Química Física, Facultad de Química, Universidad de Salamanca, 37008 Salamanca, Spain.
authors: Manuel G
authors: MG
authors: Roig
authors: Institute of Microbiology and Infection, University of Birmingham, Birmingham B152TT, United Kingdom.
authors: Vassiliy N
authors: VN
authors: Bavro
authors: Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense 400, São Carlos, SP 13560-970, Brazil.
authors: João R C
authors: JR
authors: Muniz
authors: Departamento de Bioquímica y Biología Molecular, Facultad de Biología, Universidad de Salamanca, 37007 Salamanca, Spain.
authors: Valery L
authors: VL
authors: Shnyrov
authors: Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense 400, São Carlos, SP 13560-970, Brazil. Electronic address: ipolikarpov@ifsc.usp.br.
authors: Igor
authors: I
authors: Polikarpov
mesh_terms: D028023:Arecaceae / Q000201:enzymology*; D018360:Crystallography, X-Ray; D009195:Peroxidase / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary
chemical_list: D010940:Plant Proteins; D009195:Peroxidase
keywords: Chamaerops excelsa; Oxidoreductases; Plant peroxidase; Protein crystallography; Protein oligomerization