@prefix ex: <https://sparql.uniprot.org/.well-known/sparql-examples/> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix schema: <https://schema.org/> .
@prefix sh: <http://www.w3.org/ns/shacl#> .

ex:6 a sh:SPARQLExecutable,
        sh:SPARQLSelectExecutable ;
    rdfs:comment "Select all cross-references to external databases of the category <a href=\"https://www.uniprot.org/database?query=category_exact%3A%223D%20structure%20databases%22\">'3D structure databases'</a> of UniProtKB entries that are classified with the keyword <a href=\"https://www.uniprot.org/keywords/5\">'Acetoin biosynthesis (KW-0005)'</a>"^^rdf:HTML ;
    sh:prefixes _:sparql_examples_prefixes ;
    sh:select """PREFIX keywords: <http://purl.uniprot.org/keywords/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX up: <http://purl.uniprot.org/core/>

SELECT DISTINCT ?link
WHERE
{
    ?protein a up:Protein .
    ?protein up:classifiedWith keywords:5 .
    ?protein rdfs:seeAlso ?link .
    ?link up:database ?db .
    ?db up:category '3D structure databases'
}""" ;
    schema:keywords "cross-reference" , "3D structure" , "keyword" ;
    schema:target <https://sparql.uniprot.org/sparql/> .