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Biochemical properties of the human guanylate binding protein 5 and a tumor‐specific truncated splice variant
Author(s) -
Wehner Mark,
Herrmann Christian
Publication year - 2010
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2010.07586.x
Subject(s) - splice , computational biology , chemistry , biology , biochemistry , gene
The human guanylate binding protein 5 (hGBP5) belongs to the family of interferon‐γ‐inducible large GTPases, which are well known for their high induction by pro‐inammatory cytokines. The cellular role of this protein family is unclear at this point, but there are indications for antiviral and antibacterial activity of hGBP1. hGBP5 exists in three splice variants, forming two different proteins, of which the tumor‐specic one is C‐terminally truncated by 97 amino acids, and therefore lacks the CaaX motif for geranylgeranylation. Here we present biochemical data on the splice variants of hGBP5. We show that, unlike hGBP1, hGBP5a/b and hGBP5ta do not bind GMP or produce any GMP during hydrolysis despite the fact the residues involved in GMP production from hGBP1 are conserved in hGBP5. Hydrolysis of GTP is concentration‐dependent and shows weak self‐activation. Thermodynamic studies showed strongly negative entropic changes during nucleotide binding, which reect structural ordering in the protein during nucleotide binding. These structural changes were also observed during changes in the oligomerization state. We observed only a minor inuence of the C‐terminal truncation on hydrolysis, nucleotide binding and oligomerization of hGBP5. Based on these similarities we speculate that the missing C‐terminal part, which also carries the geranylgeranylation motif, is the reason for the dysregulation of hGBP5′s function in lymphoma cells. Structured digital abstract• MINT‐7555035 , MINT‐7555053 : hGBP5 a/b (uniprotkb: Q96PP8 ) and hGBP5 a/b (uniprotkb: Q96PP8 ) bind ( MI:0407 ) by molecular sieving ( MI:0071 ) • MINT‐7555028 , MINT‐7555044 : hGBP5ta (uniprotkb: Q86TM5 ) and hGBP5ta (uniprotkb: Q86TM5 ) bind ( MI:0407 ) by molecular sieving ( MI:0071 )