Biomaterial Database

Crystal structure of horseradish peroxidase C at 2.15 A resolution. 1997

M Gajhede, and D J Schuller, and A Henriksen, and A T Smith, and T L Poulos

Department of Chemistry, University of Copenhagen, Denmark. gajhede@jerne.ki.ku.dk

The crystal structure of horseradish peroxidase isozyme C (HRPC) has been solved to 2.15 A resolution. An important feature unique to the class III peroxidases is a long insertion, 34 residues in HRPC, between helices F and G. This region, which defines part of the substrate access channel, is not present in the core conserved fold typical of peroxidases from classes I and II. Comparison of HRPC and peanut peroxidase (PNP), the only other class III (higher plant) peroxidase for which an X-ray structure has been completed, reveals that the structure in this region is highly variable even within class III. For peroxidases of the HRPC type, characterized by a larger FG insertion (seven residues relative to PNP) and a shorter F' helix, we have identified the key residue involved in direct interactions with aromatic donor molecules. HRPC is unique in having a ring of three peripheral Phe residues, 142, 68 and 179. These guard the entrance to the exposed haem edge. We predict that this aromatic region is important for the ability of HRPC to bind aromatic substrates.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010544	Peroxidases		Ovoperoxidase
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D006418	Heme	The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.	Ferroprotoporphyrin,Protoheme,Haem,Heme b,Protoheme IX
D006735	Horseradish Peroxidase	An enzyme isolated from horseradish which is able to act as an antigen. It is frequently used as a histochemical tracer for light and electron microscopy. Its antigenicity has permitted its use as a combined antigen and marker in experimental immunology.	Alpha-Peroxidase,Ferrihorseradish Peroxidase,Horseradish Peroxidase II,Horseradish Peroxidase III,Alpha Peroxidase,II, Horseradish Peroxidase,III, Horseradish Peroxidase,Peroxidase II, Horseradish,Peroxidase III, Horseradish,Peroxidase, Ferrihorseradish,Peroxidase, Horseradish
D006860	Hydrogen Bonding	A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.	Hydrogen Bonds,Bond, Hydrogen,Hydrogen Bond
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein