Using structural-based protein engineering to modulate the differential inhibition effects of SAUGI on human and HSV uracil DNA glycosylase

Abstract

Uracil-DNA glycosylases (UDGs) are highly conserved proteins that can be found in a wide range of organisms, and are involved in the DNA repair and host defense systems. UDG activity is controlled by various cellular factors, including the uracil-DNA glycosylase inhibitors, which are DNA mimic proteins that prevent the DNA binding sites of UDGs from interacting with their DNA substrate. To date, only three uracil-DNA glycosylase inhibitors, phage UGI, p56, and Staphylococcus aureus SAUGI, have been determined. We show here that SAUGI has differential inhibitory effects on UDGs from human, bacteria, Herpes simplex virus (HSV; human herpesvirus 1) and Epstein-Barr virus (EBV; human herpesvirus 4). Newly determined crystal structures of SAUGI/human UDG and a SAUGI/HSVUDG complex were used to explain the differential binding activities of SAUGI on these two UDGs. Structural-based protein engineering was further used to modulate the inhibitory ability of SAUGI on human UDG and HSVUDG. The results of this work extend our understanding of DNA mimics as well as potentially opening the way for novel therapeutic applications for this kind of protein.

Structural insights into the interaction between phytoplasmal effector causing phyllody 1 and MADS transcription factors

“…The binding affinity of PHYL1 PnWB and SEP3_K was determined by surface plasmon resonance using a BIAcore T200 (GE Healthcare) according to the protocols that were used in our previous studies (Wang et al ., ). First, using the standard amine coupling method, the anti‐His antibody was immobilized on a CM5 chip surface.…”

New paradigm of functional regulation by DNA mimic proteins: Recent updates

“…Like UGI and p56, SAUGI targets UDGs from different species . SAUGI's greatest inhibitory activity is on the UDGs from Herpes simplex virus (HSV) and Epstein–Barr virus (EBV).…”

“…It is also effective against S. aureus UDG (SAUDG) and human UDG but has almost no effect on Mycobacterium tuberculosis UDG (TBUDG) . Structures for SAUGI/SAUDG, SAUGI/human UDG, and SAUGI/HSVUDG complexes have been determined, providing useful insights into SAUGI/UDG interactions . These structures show that SAUGI targets the UDGs’ DNA binding regions, as in the example of SAUGI/human UDG (Fig.…”

“…Meanwhile, bacterial DMPs such as Myxococcus xanthus CarS, Neisseria meningitidis DMP19 (DMP 19 kDa), and Bacillus subtilis AbbA function as antirepressors that affect gene expression (10)(11)(12). DMPs can also affect DNA repair (13)(14)(15)(16)(17)(18)(19) as well as the DNA package in living cells (20)(21)(22)(23)(24).…”

Functional Analysis on a Naturally Occurring Variant of the Staphylococcus Aureus Uracil DNA Glycosylase Inhibitor

“…According to another theory, the SAUGI protein has an inherently increased affinity towards viral UDGs and this may also be further tailored, e.g. inhibition of herpes viral UDG can be largely elevated [16].…”