Determinants restricting ACE2 recognition of MERS-related coronaviruses in bats

Phylogenetically distant coronaviruses have evolved to employ ACE2 as their common receptors, including NL63 and many Severe acute respiratory syndrome (SARS) coronavirus-related viruses[1][1]. Recently, we found two Middle East respiratory syndrome coronaviruses (MERS-CoV)-related bat coronaviruses, NeoCoV and PDF-2180, also use Angiotensin-converting enzyme 2(ACE2) but not MERS-CoV receptor dipeptidyl peptidase 4 (DPP4) for entry[2][2]. Receptor binding domain (RBD)-binding and pseudovirus entry assays based on a wide range of bat ACE2 orthologs revealed that the two viruses strongly prefer ACE2 from Yangochiropteran bats as compared with Yinpterochiropteran bats, which is not observed in NL63 and SARS-CoV-2. Genetic and structural analyses of the virus-receptor interactions of 50 bat ACE2 orthologs pointed to four crucial host range determinants in two viral binding loops on ACE2. Subsequent functional verifications via mutagenesis on representative ACE2 orthologs confirmed the importance of these determinants on human and bat cells. Remarkably, NeoCoV-T510F, a mutation previously shown to acquire human ACE2 recognition, displayed an expanded potential host range covering most tested bat ACE2, probably due to its reinforced interaction with an evolutionary conserved hydrophobic pocket. Our results elucidated the molecular mechanisms for the species-specific ACE2 usage of MERS-related viruses, offering basic information for assessing the zoonotic risk of these ACE2 utilizing merbecoviruses. ### Competing Interest Statement The authors have declared no competing interest. [1]: #ref-1 [2]: #ref-2