code: public static String toLoopMmCifHeaderString(String categoryName, String className) throws ClassNotFoundException {
  		StringBuilder str = new StringBuilder();
  
  		str.append(SimpleMMcifParser.LOOP_START+newline);
  
  		Class<?> c = Class.forName(className);
  
  		for (Field f : getFields(c)) {
  			str.append(categoryName+"."+f.getName()+newline);
  		}
  
  		return str.toString();
  	}
docs: Produces a mmCIF loop header string for the given categoryName and className.
  className must be one of the beans in the {@link org.biojava.nbio.structure.io.mmcif.model} package
  @param categoryName
  @param className
  @return
  @throws ClassNotFoundException if the given className can not be found