Code examples: curl
SELECT ?virus ?virusLabel ?protein ?proteinLabel ?refseq ?uniprot WHERE {
  VALUES ?virus {
    wd:Q82069695 # SARS-CoV-2
    wd:Q16983360 # HKU1
    wd:Q16991954 # OC43
    wd:Q8351095  # NL63 
    wd:Q16983356 # 229E
    wd:Q4902157  # MERS-CoV
    wd:Q278567   # SARS-CoV
  }
  ?protein wdt:P703 ?virus ; wdt:P31 wd:Q8054 .
  OPTIONAL { ?protein wdt:P637 ?refseq }
  OPTIONAL { ?protein wdt:P352 ?uniprot }
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en,en". }
} ORDER BY ?virus
curl -s https://raw.githubusercontent.com/egonw/SARS-CoV-2-Queries/master/sparql/virusProteinsAll.rq | sed 's+<lang/>+en+' > virusProteinsAll.rq
curl -H "Accept: text/tab-separated-values" -G https://query.wikidata.org/bigdata/namespace/wdq/sparql --data-urlencode query@virusProteinsAll.rq
This SPARQL query is available under CCZero.