Modified polymerases for improved incorporation of nucleotide analogues

An altered family B archaeal polymerase comprising at least one amino acid substitution mutation at the position functionally equivalent to Lys477 in the wild-type 9° N DNA polymerase amino acid sequence of SEQ ID NO:5, wherein the substitution mutation is homologous to Lys477Met, and wherein the altered polymerase comprises an amino acid sequence that is at least 80% identical to SEQ ID NO:10, and wherein the altered polymerase further comprises substitution mutations at one or more positions functionally equivalent to Asp141 and/or Glu143 in the 9° N DNA polymerase amino acid sequence.