Yes, I have just done that. They are protein. But if they are protein, why no diffraction? That's intriguing.
________________________________ 寄件人﹕ Jürgen Bosch <jubo...@jhsph.edu> 收件人﹕ CCP4BB@JISCMAIL.AC.UK 傳送日期﹕ 2010/4/19 (一) 10:57:40 AM 主題： Re: [ccp4bb] Mysterious Crystals? Fish and wash some crystals then run them on a SDS-gel, then you will know for sure if it's protein or not. J僡gen On Apr 18, 2010, at 10:46 PM, tat cheung cheng wrote: Hi all, > >I have got some crystals, the purified protein was in Tris buffer with 300mM >NaCl for crystallization. they grew in light weight PEG, PEG400 or monomethyl >ethyl PEG500, they were needle shaped, could be long (~0.2mm) but very thin >all the time and sometimes grew into sea-urchin like needle cluster. >What interesting is, when i gridded crystallization conditions against pH or >PEG amount, the crystals sizes and shapes varied, and the crystals were >fragile so i believed they were protein crystals in nature. But upon X-ray >diffraction, they gave no reflection at all, not even a faint spot. >I wonder, beside silly mistakes like misalignment of the crystal to the beam, >not enough exposure time, what could be the reason for this mysterious >crystals? Are they protein or PEG or what? >Thanks very much. > >Tc > > > > > - J僡gen Bosch Johns Hopkins Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Phone: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-3655 http://web.mac.com/bosch_lab/
