Biochemical and structural characterization of a novel arginine kinase from the spider Polybetes pythagoricus

• Published in: PeerJ (San Francisco, CA) Vol. 5; p. e3787
• Main Authors: Laino, Aldana, Lopez-Zavala, Alonso A, Garcia-Orozco, Karina D, Carrasco-Miranda, Jesus S, Santana, Marianela, Stojanoff, Vivian, Sotelo-Mundo, Rogerio R, Garcia, Carlos Fernando
• Format: Journal Article
• Language: English
• Published: United States PeerJ. Ltd 11-09-2017; PeerJ, Inc; PeerJ Inc
• Subjects: Allergen; Allergens; Allergy and Clinical Immunology; Analysis; Arachnida; Arginine; Arginine kinase; Arthropoda; Biochemistry; Biophysics; cDNA cloning; Cloning; Complementary DNA; Composition; Crustaceans; Crystal structure; DNA structure; E coli; Energy metabolism; Enzymes; Gene expression; Genetic aspects; Homeostasis; Kinases; Laboratories; MATERIALS SCIENCE; Metabolism; Molecular biology; Nucleotides; Open conformation; Phosphagen; Phylogenetics; Physiological aspects; Physiology; Polybetes pytagoricus; Predators; Properties; Proteins; Solenopsis invicta; Spider; Spider venoms; Spiders; Terrestrial ecosystems; Zoology; United States > US; Arachnida; cDNA cloning; Polybetes pytagoricus; Open conformation; Arthropoda; Phosphagen; Arginine kinase; Spider; Allergen; Crystal structure
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.3787

Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Argentininan spider
(
AK), from its complementary DNA to the crystal structure. The
AK cDNA from muscle was cloned, and it is comprised of 1068 nucleotides that encode a 384-amino acids protein, similar to other invertebrate AKs. The apparent Michaelis-Menten kinetic constant (
) was 1.7 mM with a
of 75 s
. Two crystal structures are presented, the apo
AK and
AK bound to arginine, both in the
conformation with the active site lid (residues 310-320) completely disordered. The guanidino group binding site in the apo structure appears to be organized to accept the arginine substrate. Finally, these results contribute to knowledge of mechanistic details of the function of arginine kinase.