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The Pou-specific domain is located on the N-terminal site of the Oct-4 sequence and precisely from the 131th  amino acid to the 205th. The POU-specific domain is able to bind autonomously the DNA with the binding consensus : [gAATAT(G/T)CA]. This is the thanks to a specific motif, the helix-turn-helix. At its name suggests, this pattern is composed by two [[α helix]] linked by an amino acids sequence which corresponds to the turn. The second helix is the most involved in the DNA binding. Indeed, this helix is able to carry out hydrogen bonds and Van der Waalts interactions with bases in the major groove of DNA. The first helix allows to stabilize the complex DNA-protein. In the Pou specific domain of the transcription factor Oct-4, there are actually 2 HTH motif linked by another alpha helix.The HTH motif is responsible of the DNA binding thanks to the first amino acid located in every helix in HTH. Indeed, this amino acid is a glutamic acid which is able to interact with the backbone phosphate and the adenine base in the DNA binding site. Thanks to bioinformatics tools, alignments were carrying out. We discover that there is a very good alignment between the Oct-4 POU domain and the Lambda Bacteriophage POU domain.