Final Report Summary - SHERPA (Structure of herpesviral cell access)
SHERPA is a post-doctoral training project in structural investigation of membrane proteins, focused on the virion fusion players of Human cytomegalovirus (HCMV), a major and wide-spread human pathogen belonging to the envelope virus family of Herpevirus. The HCMV fusion machinerypresents an unusual complexity with three different membrane protein complexes made of sevendistinct subunits. The type I transmembrane glycoproteins gB and gH / gL are strictly required forvirion-mediated membrane fusion, then for viral infectivity, in herpesviruses. GB is the protein carrying the membrane merging capability, with gH / gL providing ancillary functions. In HCMV, two different gH / gL complexes have been recognised comprising further peripheral proteins: thegO-primed gH / gL heterodimer and the heteropentamer gH / gL / pUL131A / pUL130 / pUL128. In order to obtain deeper insight into HCMV fusion machinery, gB fusion factor should be studied in its full-length trans-membrane form. So far, viral fusion proteins have been studied as recombinant truncated mutants. In particular, molecular structure models of herpesviral gB ectodomain (the portion of the protein that actually possesses the membrane merging activity) have been obtained in their post-fusion homotrimeric conformations. Several studies have shown that producing this domain of gB alone, invariably leads to this conformation and leaving unaddressed the characterisation of pre-fusion form for this important anti-viral target. The main reason for this gap is related to the troubles faced so far in obtaining biochemistry quality of full length gB proteins.
As result of the scientific work, SHERPA provided the first method for producing at biochemical quality a more representative form of herpesviral gB fusion factor, made possible a first analysis of its folding, suggesting future work to understand how this viral protein performs its role in the entry of Herpes viruses into target cells and allowed to answer the important question on possible missing antigenic elements in HCMV gB truncated ectodomain, the latter exploited at some success to develop anti-CMV subunit vaccine candidates. Furthermore, SHERPA achievements constitute entirely the deliverable 5.6 of European Union (EU)-funded project ComplexINC (grant agreement No. 270089), in which SHERPA has been included, with SHERPA researcher enrolled as local scientific manager of iBET partnership in Complex INC consortium.
The associated training was particular successful in merging animal cell biotechnology and membrane protein science with the previous expertise in molecular virology of the researcher. This merging is now continuing with the researcher managing more projects related to human and human-infecting virus membrane proteins for biochemical and, possibly, structural study. The researcher has been, indeed, enrolled as senior scientist at iBET where, alongside refining the study of herpesviral fusion factors towards a better structure-function understanding of this class of proteins, he is contributing the overall activity of iBET, one of the largest CRO in Portugal, with constant research contract services from international biotech industry.
As result of the scientific work, SHERPA provided the first method for producing at biochemical quality a more representative form of herpesviral gB fusion factor, made possible a first analysis of its folding, suggesting future work to understand how this viral protein performs its role in the entry of Herpes viruses into target cells and allowed to answer the important question on possible missing antigenic elements in HCMV gB truncated ectodomain, the latter exploited at some success to develop anti-CMV subunit vaccine candidates. Furthermore, SHERPA achievements constitute entirely the deliverable 5.6 of European Union (EU)-funded project ComplexINC (grant agreement No. 270089), in which SHERPA has been included, with SHERPA researcher enrolled as local scientific manager of iBET partnership in Complex INC consortium.
The associated training was particular successful in merging animal cell biotechnology and membrane protein science with the previous expertise in molecular virology of the researcher. This merging is now continuing with the researcher managing more projects related to human and human-infecting virus membrane proteins for biochemical and, possibly, structural study. The researcher has been, indeed, enrolled as senior scientist at iBET where, alongside refining the study of herpesviral fusion factors towards a better structure-function understanding of this class of proteins, he is contributing the overall activity of iBET, one of the largest CRO in Portugal, with constant research contract services from international biotech industry.