Dear Kannan,

your reviewer may have meant x-ray diffraction. But I must admit that this is not a chemical technique.

Furthermore an x-ray  wave length of 1,3A (~ 9,5keV; Zn Kß line) is not commonly used in XRD and a '1,3A resolution' if a far bad value for a crystallographic structure.

But nevertheless for a short introduction into protein XRD please have a look at the link.

http://www.proteinstructures.com/Experimental/Experimental/protein-crystallography.html

Dear Gerhard Martens 

Thanks for your comments. We have a protein structure solved and refined in 1.3 A resolution. But the reviewer asked like this question so i confused. 

Thanks for your response Kannan,

there is also confusion on my side.

But I am not familiar with refinement. However  the 1'.3 resolution' seems to me a very poor number when thinking on atomic positions at a  precision in the order of 0,1A. . The reviewer may have the same confusion. But refinement resolution may not be identical to coordinate precision.

However I picked up a link stating that a resolution of 2A for example ends up in a precision of better 0,2A for the coordinates. So your 1.3A are a good choice to my opinion.

But let us wait for other comments from the RG community.

http://proteopedia.org/wiki/index.php/Resolution

Thanks

Lets wait for other comments too.