Reconstruction of the Ancestral Sequence of CalsequestrinTatyana NienowBIOL 7020April 26, 2010

Calsequestrin• Calcium-binding protein

found in sarcoplasmic reticulum in muscle▫ High capacity (40-80 mol

Ca2+/molecule)▫ Medium affinity (KD = 1

mM)▫ Aspartic acid-rich tail

Calsequestrin

•CSQ1▫Found in skeletal and cardiac muscle▫Binds twice as many calcium ions as CSQ2▫Larger negative surface potential

•CSQ2▫Found only in cardiac muscle

Methods

•Collected calsequestrin sequences from NCBI▫Using refseq_rna database

•Aligned in Seaview▫Removed predicted signal sequences and

poly-Asp tails

Methods

•Phylogeny with MrBayes and RAxML•Determined ancestral sequence with

MrBayes and FastML•Corrected ancestral sequence length

▫Convert alignment to treat gaps as characters

▫Calculate ancestral form▫Use ancestral gap sequence to remove

inserted sites from original ancestral sequence

CSQ1

CSQ2

Completed Ancestral Sequences

Comparison to CSQ1 and CSQ2