diff --git a/src/mol-base/collections/column.ts b/src/mol-base/collections/column.ts
index 3517030320e279a5701720cec03365e021381301..acedf1d925c9c72ea9f2ac532cd8c009cee1a3fb 100644
--- a/src/mol-base/collections/column.ts
+++ b/src/mol-base/collections/column.ts
@@ -35,7 +35,7 @@ export interface Column<T> {
 }
 
 export function UndefinedColumn<T extends ColumnType>(rowCount: number, type: T): Column<T['@type']> {
-    const value: Column<T['@type']>['value'] = type.kind === 'str' ? row => '' : row => 0;
+    const value: Column<T['@type']>['value'] = type.isString ? row => '' : row => 0;
     return {
         '@type': type,
         isDefined: false,