How to replace underscore between digits and character or at second place (_) in protein seq header & discriptions

Question

[Neel]

Hi, I want to remove(_) sign between the accession number and their description name  like this -> ALKAOGAL_00001  Chromosomal_replication_initiator_protein_DnaA in all protein seq.
Is there any script for this please share with me.

    >ALKAOGAL_00001_Chromosomal_replication_initiator_protein_DnaA
    MEEPSIDPLAAAMPAGAAPAVRTERNVQVEGALKHTSYLNRTFTFENFVEGKSNQLARAA
    AWQVADNLKHGYNPLFLYGGVGLGKTHLMHAVGNHLLKKNPNAKVVYLHSERFVADMVKA
    LQLNAINEFKRFYRSVDALLIDDIQFFARKERSQEEFFHTFNALLEGGQQVILTSDRYPK
    EIEGLEERLKSRFGWGLTVAVEPPELETRVAILMKKAEQAKIELPHDAAFFIAQRIRSNV
    RELEGALKRVIAHSHFMGRPITIELIRESLKDLLALQDKLVSIDNIQRTVAEYYKIKISD
    LLSKRRSRSVARPRQVAMALSKELTNHSLPEIGVAFGGRDHTTVLHACRKIAQLRESDAD
    IREDYKNLLRTLTT
    >ALKAOGAL_00002_Beta_sliding_clamp
    MHFTIQREALLKPLQLVAGVVERRQTLPVLSNVLLVVEGQQLSLTGTDLEVELVGRVVLE
    DAAEPGEITVPARKLMDICKSLPNDVLIDIRVEEQKLLVKAGRSRFTLSTLPANDFPTVE
    EGPGSLNFSIAQSKLRRLIDRTSFAMAQQDVRYYLNGMLLEVNGGTLRSVATDGHRLAMC
    SLDAQIPSQDRHQVIVPRKGILELARLLTEQDGEVGIVLGQHHIRATTGEFTFTSKLVDG
    KFPDYERVLPRGGDKLVVGDRQQLREAFSRTAILSNEKYRGIRLQLSNGLLKIQANNPEQ
    EEAEEEVQVEYNGGNLEIGFNVSYLLDVLGVIGTEQVRFILSDSNSSALVHEADNDDSAY
    VVMPMRL

Thank you!

[cpad0112]

$ sed '/^>/ s/_/ /2g' test.fa

[Neel]

Thank you so much

Answer 1

[Jeremy]

You should be able to use the following:

sed 's/_/ /2'

Note the space between the last two slashes.

[Neel]

Thank you! Now it work.