This project requires Python 2.7, which is a pain to set up on CentOS 5. Do that first. Install Python 2.7, setuptools, pip, and virtualenv.
sudo apt-get install python-dev python-pip python-virtualenv
useradd -m datastore
su - datastore
virtualenv --no-site-packages ~/env
echo "source ~/env/bin/activate" >> ~/.bash_profile
. ~/.bash_profile
git clone https://github.com/iPlantCollaborativeOpenSource/python-irodsclient.git
pip install -e python-irodsclient
cd ~
git clone git://github.com/iPlantCollaborativeOpenSource/sra.git
cd sra
python setup.py develop
sudo ~/env/sra/bin/pserve production.ini --log-file=sra.log --daemon