Sequence analysis
Homology search was made with b asic l ocala lignment s earch t ool (BLAST) by using Clustal W (http://www.ebi.ac.uk/Tools/msa/clustalo/). Signal sequence predictions were made by Target P (http://www.cbs.dtu.dk/services/TargetP/). Nucleotide sequence data were taken from the database at the following website: <http://www.ncbi.nlm.nih.gov/>.