split - Extract a fixed-length character in R -

i have attribute consisting dna sequences , translate amino name. need split sequence in fixed-length character 3. here sample of data

data=c("aatagacgt","tgaccc","aaatcactcttt") 

how can extract into:

[1] "aat" "aga" "cgt" [2] "tga" "ccc"  [3] "aaa" "tca" "ctc" "ttt" 

so far can find how split string given regex separator

try

strsplit(data, '(?<=.{3})', perl=true) 

or

library(stringi) stri_extract_all_regex(data, '.{1,3}')