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

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 Polybetes pythagoricus ( PpAK), from its complementary DNA to the crystal structure. The PpAK 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 ( K m) was 1.7 mM with a k cat of 75 s –1. Two crystal structures are presented, the apo PvAK and PpAK bound to arginine, both in the open 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. Lastly, these results contribute to knowledge of mechanistic details of the function of arginine kinase.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [1] ;  [4] ;  [3] ;  [1]
  1. Univ. Nacional de La Plata, Buenos Aires (Argentina)
  2. Univ. de Sonora, Sonora (Mexico)
  3. Centro de Investigacion en Alimentacion y Desarrollo, Sonora (Mexico)
  4. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Report Number(s):
BNL-203458-2018-JAAM
Journal ID: ISSN 2167-8359
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
PeerJ
Additional Journal Information:
Journal Volume: 5; Journal ID: ISSN 2167-8359
Publisher:
PeerJ Inc.
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Arginine kinase; Spider; cDNA cloning; Crystal structure; Phosphagen; Polybetes pytagoricus; Arthropoda; Arachnida; Open conformation; Allergen
OSTI Identifier:
1435730