Enhancing the apo protein tyrosine phosphatase non-receptor type 2 crystal soaking strategy through
Stephanie M Bester1, Rebecca Linwood1, Ryoko Kataoka1
1Pfizer Boulder Research and Development, Boulder, CO 80301, USA.
Abstract:
Protein tyrosine phosphatase non-receptor type 2 (PTPN2) has recently been recognized as a promising target for cancer immunotherapy. Despite extensive structural and functional studies of other protein tyrosine phosphatases, there is limited structural understanding of PTPN2. Currently, there are only five published PTPN2 structures and none are truly unbound due to the presence of a mutation, an inhibitor or a loop (related to crystal packing) in the active site. In this report, a novel crystal packing is revealed that resulted in a true apo PTPN2 crystal structure with an unbound active site, allowing the active site to be observed in a native apo state for the first time. Key residues related to accommodation in the active site became identifiable upon comparison with previously published PTPN2 structures. Structures of PTPN2 in complex with an established PTPN1 active-site inhibitor and an allosteric inhibitor were achieved through soaking experiments using these apo PTPN2 crystals. The increased structural understanding of apo PTPN2 and the ability to soak in inhibitors will aid the development of future PTPN2 inhibitors.
Insights
Protein tyrosine phosphatase non-receptor type 2 (PTPN2) is a cancer immunotherapy target. A novel crystal structure reveals the first true apo PTPN2 active site, aiding future inhibitor development.
Area of Science:
- Biochemistry
- Structural Biology
- Cancer Research
Background:
- Protein tyrosine phosphatase non-receptor type 2 (PTPN2) is a key target in cancer immunotherapy.
- Limited structural data exists for PTPN2, with no previously published truly unbound active site structures.
- Existing PTPN2 structures are hindered by mutations, inhibitors, or crystal packing artifacts in the active site.
Purpose of the Study:
- To determine the first true apo structure of PTPN2 with an unbound active site.
- To characterize key residues involved in active site accommodation.
- To facilitate the development of novel PTPN2 inhibitors.
Main Methods:
- Novel crystal packing approach to obtain a native apo PTPN2 structure.
- X-ray crystallography to resolve the PTPN2 active site.
- In-situ soaking experiments with known inhibitors using apo PTPN2 crystals.
Main Results:
- A novel crystal packing enabled the determination of a true apo PTPN2 crystal structure.
- The unbound active site of PTPN2 was observed in its native state for the first time.
- Comparison with prior structures identified key residues for active site accommodation.
- Structures of PTPN2 in complex with PTPN1 and allosteric inhibitors were successfully generated.
Conclusions:
- The determined apo PTPN2 structure provides unprecedented insight into its native active site.
- This structural understanding is crucial for designing targeted PTPN2 inhibitors.
- The ability to soak inhibitors into apo crystals offers a versatile platform for drug discovery.
